- 0 A.D. (C, C++, JavaScript, GPL-2.0, beta)
- 1255 Burgomaster (JavaScript, GPL-3.0, beta)
- 1oom (C, GPL-2.0, mature)
- 2006-rebotted (Java, 2-clause BSD, mature)
- 2006scape (Java, GPL-3.0, mature)
- 2009scape (Java, Kotlin, AGPL-3.0, mature)
- 2048 Python (Python, MIT, mature)
- 2048-in-terminal (C, MIT, mature)
- 2048 (JavaScript, Java, MIT, mature)
- 2H4U (C++, GPL-2.0, mature, inactive since 2007)
- 3D Pong (C, GPL-2.0, beta, inactive since 2004)
- 3d.city (JavaScript, GPL-3.0, mature, inactive since 2016)
- 3Dc (C, GPL-2.0, mature, inactive since 2000)
- 3DWorld (C++, GPL-3.0, mature)
- 4D Maze Game (Java, Public domain, mature, inactive since 2008)
- 4D-TRIS (C, GPL-2.0, mature, inactive since 2012)
- 54321 (C++, Custom, mature, inactive since 2001)
- A Dark Room (JavaScript, MPL-2.0, mature)
- A Planet's Revenge (Python, GPL-3.0, beta, inactive since 2008)
- A7Xpg (D, 2-clause BSD, beta, inactive since 2005)
- Abe's Amazing Adventure (C, GPL-2.0, mature, inactive since 2005)
- Abuse 1996 (C++, Lisp, Custom, Public domain, GPL-2.0, WTFPL, mature, inactive since 2016)
- Abuse (C++, Lisp, Public domain, GPL-2.0, WTFPL, mature, inactive since 2011)
- Achtung, die Kurve! (JavaScript, AGPL-3.0, mature)
- ACM (C, GPL-2.0, mature, inactive since 2000)
- AdaDoom3 (Ada, GPL-3.0, beta)
- AdaGate (Ada, GPL-3.0, mature)
- Adanaxis (C++, GPL-2.0, mature, inactive since 2007)
- AdaVenture (Ada, GPL-3.0, mature)
- Advanced Strategic Command (C++, GPL-2.0, mature)
- adventure engine (Lua, MIT, mature, inactive since 2013)
- Afternoon Stalker (C++, GPL-2.0, mature, inactive since 2012)
- AI Wars (Python, MIT, beta, inactive since 2010)
- Airstrike (C, GPL-2.0, beta, inactive since 2014)
- Aisleriot (C, Scheme, GPL-3.0, mature)
- Ajax3d (JavaScript, GPL-2.0, beta, inactive since 2007)
- Aklabeth (C, GPL-2.0, mature, inactive since 2004)
- Alchemy Quest (C++, GPL-2.0, mature)
- Aleph One (C++, Lua, GPL-3.0, mature)
- Alex the Allegator 4 (C, GPL-2.0, mature, inactive since 2003)
- Alien Assault Traders (PHP, GPL-2.0, beta, inactive since 2009)
- Alimer (C++, MIT, beta)
- Allure of the Stars (Haskell, AGPL-3.0, beta)
- Ambermoon.net (C#, GPL-3.0, mature)
- Ambrose3D (C++, zlib, beta, inactive since 2007)
- Amphetamine (C, GPL-2.0, beta, inactive since 2008)
- Anagramarama (C, GPL-2.0, beta, inactive since 2002)
- Anarch (C, C++, CC0, mature)
- Ancient Beast (JavaScript, AGPL-3.0, mature)
- AndEngine (Java, Apache-2.0, mature, inactive since 2013)
- Andor's Trail (Java, GPL-2.0, beta)
- android-chess (Java, C++, MIT, mature)
- Angband (C, GPL-2.0, mature)
- Angry Birds in Python (Python, MIT, mature, inactive since 2017)
- AnKi 3D engine (C++, 3-clause BSD, beta)
- Annex: Conquer the World (Lua, GPL-3.0, mature, inactive since 2014)
- Antares (C++, LGPL-3.0, beta)
- Anteform (Lua, GPL-3.0, beta)
- AntiChess (Java, MIT, beta, inactive since 2003)
- antiyoy (Java, GPL-3.0, beta)
- Anura (C, C++, zlib, mature)
- Anuto (Java, GPL-2.0, mature)
- Apple Flinger (Java, GPL-3.0, mature)
- Apricots (C++, GPL-2.0, beta, inactive since 2003)
- aquastax (JavaScript, MIT, beta)
- Arashi-JS (JavaScript, GPL-2.0, beta, inactive since 2010)
- Arcane-Engine (C++, MIT, beta)
- ArchaicQuest II (C#, MIT, mature)
- Ardentryst (Python, GPL-3.0, mature, inactive since 2009)
- Ares Dogfighter (Java, GPL-3.0, beta, inactive since 2016)
- Argentum Online (Visual Basic, GPL-2.0, AGPL-3.0, beta, inactive since 2014)
- Armagetron Advanced (C++, GPL-2.0, mature)
- Armies (C++, GPL-3.0, mature, inactive since 2007)
- Armor Alley (JavaScript, CC-BY-NC-3.0, beta)
- Arrakis (Basic, Custom, mature, inactive since 2000)
- Artillery Duel Reloaded (Python, GPL-3.0, beta, inactive since 2012)
- Arx Libertatis (C++, GPL-3.0, mature)
- asdf (JavaScript, MIT, mature)
- AssaultCube (C, C++, Custom, mature, inactive since 2018)
- AstroMenace (C++, C, GPL-3.0, mature)
- ativayeban (C, C++, GPL-2.0, mature, inactive since 2015)
- Atomic Tanks (C++, C, GPL-2.0, mature, inactive since 2016)
- Atomiks (C, Objective-C, GPL-3.0, mature, inactive since 2015)
- Atomix (C, GPL-2.0, mature)
- Atrinik (C, Python, GPL-2.0, mature, inactive since 2016)
- Attal: Lords of doom (C++, GPL-2.0, mature, inactive since 2008)
- Augustus (C, C++, AGPL-3.0, mature)
- Aussenposten (JavaScript, MIT, beta, inactive since 2015)
- Avanor (C++, Lua, C, GPL-2.0, beta, inactive since 2008)
- Awkaster (AWK, MIT, mature, inactive since 2017)
- Azimuth (C, GPL-3.0, mature)
- BAB BE U (Lua, MIT, mature)
- back-to-nature-c64-remake (Java, MIT, mature, inactive since 2015)
- Backbone Game Engine (JavaScript, MIT, beta, inactive since 2016)
- Bacon2D (C++, MIT, beta, inactive since 2018)
- Balder2D (C++, GPL-2.0, beta, inactive since 2009)
- Ball and Paddle (C++, Scheme, Script, GPL-3.0, beta, inactive since 2009)
- Ball And Wall (JavaScript, MIT, mature, inactive since 2015)
- Ballerburg SDL (C, GPL-3.0, mature)
- Banania (JavaScript, MIT, mature)
- Barbarian (Basic, ?, mature, inactive since 2014)
- Barony (C++, GPL-3.0, mature)
- Bastet (C++, GPL-2.0, beta, inactive since 2018)
- Batalla Naval (C, Script, GPL-2.0, mature, inactive since 2002)
- Batrachians (C++, GPL-2.0, beta, inactive since 2012)
- Battery (Java, EPL-2.0, Custom, mature, inactive since 2009)
- Battle City (C, C++, Pascal, GPL-3.0, mature, inactive since 2013)
- Battle Tanks (C++, GPL-2.0, mature, inactive since 2009)
- Battlefield Java (Java, GPL-3.0, beta, inactive since 2011)
- Battleround (Java, Apache-2.0, beta, inactive since 2015)
- Battles of Antargis (C, C++, GPL-2.0, beta, inactive since 2014)
- Beat Feet (Kotlin, GPL-3.0, mature)
- Beat Harvester (Python, GPL-2.0, beta, inactive since 2009)
- Belote (Java, GPL-3.0, beta)
- Bemuse (JavaScript, TypeScript, AGPL-3.0, mature)
- Berusky II (C++, GPL-3.0, beta)
- Berusky (C++, GPL-3.0, mature)
- Betrayer's Moon Tactics (JavaScript, GPL-2.0, beta, inactive since 2006)
- BetterSpades (C, GPL-3.0, beta)
- Between (PHP, C++, ?, beta, inactive since 2010)
- Beyond All Reason (Lua, GPL-2.0, beta)
- Billiards (Lua, Objective-C, GPL-3.0, beta, inactive since 2012)
- Biniax (C, zlib, mature, inactive since 2012)
- Biogenesis (Java, GPL-2.0, beta)
- Birth of the Empires (C++, Custom, mature, inactive since 2016)
- Bitfighter (C, C++, GPL-2.0, mature)
- BitRiot (C++, Apache-2.0, beta, inactive since 2017)
- Black Shades Elite (C, C++, GPL-2.0, beta, inactive since 2007)
- Black Shades (C, GPL-3.0, mature)
- BlackNova Traders (PHP, JavaScript, GPL-2.0, beta, inactive since 2012)
- Blackvoxel (C++, GPL-3.0, mature)
- Bladecoder Adventure Engine (Java, Apache-2.0, mature)
- BlakedAwesomenaughts (JavaScript, PHP, MIT, beta, inactive since 2015)
- Blasphemer (None, Python, None, mature, inactive since 2017)
- Blinken (C++, GPL-2.0, mature)
- Blitwizard (C, C++, Lua, zlib, beta, inactive since 2015)
- Blitzkrieg (Java, GPL-3.0, beta, inactive since 2012)
- Blob Wars : Attrition (C, C++, GPL-3.0, mature)
- Blob Wars Episode 2 : Blob And Conquer (C++, GPL-2.0, mature, inactive since 2016)
- Blobby Volley 2 (C++, GPL-2.0, mature)
- Bloboats (C++, GPL-2.0, mature, inactive since 2006)
- Blobwars: Metal Blob Solid (C++, C, GPL-2.0, mature)
- Block Attack - Rise of the Blocks (C++, GPL-2.0, mature)
- Block Puzzle Stone Wars (Java, MIT, mature)
- BlockOut II (C++, GPL-2.0, mature, inactive since 2014)
- Blockrain (JavaScript, MIT, beta, inactive since 2017)
- Bloodmasters (C#, GPL-2.0, mature, inactive since 2008)
- Blue Nebula (C, C++, zlib, mature)
- boardgame.io (JavaScript, TypeScript, MIT, beta)
- BobBall (Java, 2-clause BSD, mature, inactive since 2017)
- Bobby (TypeScript, AGPL-3.0, mature)
- BomberClone (C, GPL-2.0, beta, inactive since 2010)
- Bombermaaan (C++, GPL-3.0, mature, inactive since 2010)
- Bombic2 (C++, GPL-2.0, beta, inactive since 2010)
- Bombic (C++, Objective-C, GPL-2.0, beta, inactive since 2005)
- Bombman (Python, CC0, mature)
- Boohu (Go, ISC, beta)
- BOOM: Remake (C++, Custom, mature)
- Bos Wars (C++, GPL-2.0, mature)
- Boson (C++, C, GPL-2.0, beta, inactive since 2006)
- Boulder Dash (Java, MIT, mature, inactive since 2015)
- Bouncy the Hungry Rabbit (Python, GPL-2.0, mature, inactive since 2007)
- Brain Workshop (Python, GPL-2.0, mature, inactive since 2011)
- brainblast (C++, C, GPL-3.0, beta, inactive since 2018)
- bratwurst (Lisp, GPL-2.0, mature, inactive since 2009)
- Breakout-VR (C#, MIT, beta, inactive since 2017)
- Bridge Command (C++, GPL-2.0, mature)
- Brikx (C++, GPL-2.0, beta, inactive since 2009)
- Briquolo (C++, GPL-2.0, mature, inactive since 2008)
- British Bingo (JavaScript, GPL-3.0, mature)
- Brogue (C, AGPL-3.0, mature)
- BrowserQuest (JavaScript, MPL-2.0, mature)
- Brutal Chess (C++, GPL-2.0, beta, inactive since 2007)
- BStone (C++, GPL-2.0, mature)
- buggyGame (Python, GPL-2.0, beta, inactive since 2007)
- Build engine (C, C++, Custom, mature)
- BurgerSpace (C++, GPL-2.0, mature, inactive since 2013)
- Bygfoot (Java, GPL-2.0, beta)
- BZFlag (C++, LGPL-2.1, MPL-2.0, mature)
- C-Dogs SDL (C, GPL-2.0, mature)
- C-evo (Pascal, Public domain, GPL-3.0, mature, inactive since 2013)
- C3DE (C#, MIT, beta)
- c64-nuclearreaction (C, Assembly, GPL-3.0, mature, inactive since 2014)
- Cabbages and Kings (Python, MIT, mature)
- Cadaver (C++, GPL-2.0, beta, inactive since 2009)
- CaesarIA (C++, JavaScript, C, GPL-3.0, beta)
- Cafu Engine (C++, MIT, beta, inactive since 2018)
- Candle (C, MIT, beta)
- Candy Box 2 (TypeScript, JavaScript, GPL-3.0, mature, inactive since 2013)
- Candy Memory (Java, GPL-2.0, mature, inactive since 2018)
- Cannon Smash (C++, GPL-2.0, beta, inactive since 2003)
- Cannonball (C++, MAME, beta)
- Canta (Python, GPL-3.0, beta, inactive since 2011)
- canvas-tetris (JavaScript, MIT, mature, inactive since 2018)
- Caph (C, GPL-3.0, mature, inactive since 2010)
- Captain Blood (C++, C, GPL-3.0, mature)
- Card Stories (JavaScript, Python, AGPL-3.0, beta, inactive since 2012)
- Carnage3D (C++, C, MIT, beta)
- Cart Life (AGS Script, Custom, mature, inactive since 2014)
- Castle of the Winds in Elm (Elm, JavaScript, MIT, beta)
- Castle of the Winds (JavaScript, MIT, beta, inactive since 2016)
- Castle-Combat (Python, GPL-2.0, beta, inactive since 2006)
- Castor3D (C++, MIT, beta)
- Cat Mother Dead Justice (C++, 3-clause BSD, GPL-2.0, beta, inactive since 2003)
- Cataclysm: Dark Days Ahead (C++, CC-BY-SA-3.0, mature)
- Cataclysm (C++, CC-BY-SA-3.0, beta, inactive since 2012)
- Catacomb 3-D (C, C++, GPL-2.0, mature, inactive since 1991)
- Catacomb (Pascal, GPL-2.0, mature, inactive since 1989)
- CatacombGL (C++, GPL-3.0, beta)
- CatacombSDL (C, GPL-2.0, mature, inactive since 2014)
- Catan Dice Game (Java, GPL-3.0, mature)
- Catch Challenger (C++, C, GPL-3.0, mature)
- Catch The Cat (TypeScript, JavaScript, MIT, mature)
- Cattle Bity (TypeScript, MIT, mature)
- CaveExpress (C, JavaScript, GPL-3.0, mature)
- CavePacker (JavaScript, C, C++, Lua, GPL-3.0, mature)
- CAVEZ of PHEAR (C, GPL-3.0, beta)
- cc94 (C++, Python, AGPL-3.0, beta)
- CCCP (C++, AGPL-3.0, beta)
- Celestron (Python, GPL-3.0, beta, inactive since 2012)
- CETech (C, C++, CC0, beta)
- chainreaction (Java, LGPL-3.0, mature, inactive since 2017)
- Chaos Esque Anthology (?, ?, mature)
- Chariot (Rust, MIT, beta, inactive since 218)
- Chess3D (JavaScript, Python, GPL-3.0, mature, inactive since 2016)
- Children of Ur (Dart, JavaScript, MIT, beta)
- Childsplay (Python, GPL-3.0, mature)
- Chocolate Doom (C, GPL-2.0, mature)
- Chocolate Duke3D (C, GPL-2.0, Custom, beta, inactive since 2016)
- Choria (C++, C, Lua, GPL-3.0, mature)
- Chroma (C, GPL-2.0, mature)
- Chromium B.S.U. (C++, Artistic License-1.0, mature)
- Chronoshift (C++, GPL-2.0, beta)
- Chrzaszcz (C++, GPL-3.0, beta, inactive since 2018)
- Chunk Stories (Kotlin, Java, LGPL-3.0, beta)
- Circus Linux! (C, GPL-2.0, mature, inactive since 2000)
- Citybound (Rust, JavaScript, AGPL-3.0, beta)
- Civ2-clone (C#, GPL-3.0, beta)
- Civil (Python, GPL-2.0, beta, inactive since 2003)
- Civilization: Call To Power 2 Source Project (C, C++, Custom, mature)
- Civitas (Java, Blender Script, GPL-2.0, beta, inactive since 2017)
- CivOne (C#, CC0, beta)
- ClanLib (C, C++, zlib, mature)
- Classic Blades of Exile (C++, GPL-2.0, mature)
- Classic RBDoom 3 BFG (C, C++, GPL-3.0, mature)
- ClassiCube (C, 3-clause BSD, mature)
- ClassicUO (C#, 4-clause BSD, beta)
- Clonepoint (C++, GPL-3.0, beta)
- Clumsy Bird (JavaScript, MIT, mature, inactive since 2017)
- CnC Remastered Collection (C++, C#, GPL-3.0, mature, inactive since 2020)
- Colditz Escape (C, GPL-3.0, mature)
- Colobot: Gold Edition (C++, GPL-3.0, mature)
- Colonization too (C++, GPL-2.0, beta, inactive since 2004)
- Coloris (Java, GPL-3.0, mature, inactive since 2020)
- Colossal Cave Adventure (Python, Apache-2.0, mature)
- Columns (C++, zlib, mature)
- Combat Simulator Project (C++, GPL-2.0, beta, inactive since 2010)
- Command Series Engine (Go, GPL-2.0, mature)
- Commander Genius (C, C++, GPL-2.0, mature)
- Commander Wars (C++, JavaScript, LGPL-3.0, mature)
- CommandoJS (JavaScript, CoffeeScript, MIT, beta, inactive since 2012)
- CommonDrops (C++, MIT, beta, inactive since 2018)
- Conquest (C++, MIT, mature)
- Conquests (C++, GPL-2.0, mature, inactive since 2012)
- Consomaton (TypeScript, MIT, mature, inactive since 2016)
- Construo (C++, GPL-3.0, beta, inactive since 2015)
- Corange (C, 2-clause BSD, beta)
- Core Breach (C, Objective-C, GPL-2.0, mature, inactive since 2012)
- Core War (C, Java, GPL-2.0, 2-clause BSD, mature)
- CorEngine (C, zlib, beta, inactive since 2015)
- CorsixTH (Lua, C++, MIT, mature)
- Cortex Command - open source (C++, C, AGPL-3.0, mature, inactive since 2019)
- Cosmo-Engine (C, GPL-2.0, beta)
- Cosmore (C, Assembly, MIT, mature)
- Cosmosmash (C++, GPL-2.0, mature, inactive since 2013)
- CoTerminalApps (Ada, GPL-3.0, mature)
- Crack Attack! (C++, GPL-2.0, mature, inactive since 2005)
- Craft (C, Python, MIT, mature, inactive since 2017)
- CrappyBird (JavaScript, MIT, mature, inactive since 2017)
- Crazy Cars (Basic, ?, mature, inactive since 2014)
- Creep Smash (Java, GPL-3.0, beta, inactive since 2011)
- Crimson Fields (C++, C, GPL-2.0, mature, inactive since 2010)
- Critical Velocity (Java, Apache-2.0, mature, inactive since 2017)
- Critterding (C++, GPL-2.0, beta, inactive since 2013)
- CroftEngine (C++, Python, LGPL-3.0, beta)
- Cross The Road (Elm, JavaScript, AGPL-3.0, mature)
- Crossfire (C, Java, GPL-2.0, mature)
- CrossUO (C, C++, GPL-3.0, mature)
- Crosswords (Java, GPL-2.0, mature)
- Crown and Cutlass (C++, C, Custom, beta, inactive since 2009)
- Crown (C, C++, Vala, MIT, beta)
- CrystalQuest (JavaScript, MIT, mature, inactive since 2017)
- Cube 2: Sauerbraten (C, C++, Custom, mature, inactive since 2020)
- Cube (C, C++, Custom, mature, inactive since 2005)
- Cubosphere (C, C++, Lua, GPL-3.0, beta)
- Cubyz (Java, GPL-3.0, beta)
- Cultivation (C++, Public domain, mature, inactive since 2010)
- Curse of War (C, C++, GPL-3.0, mature, inactive since 2014)
- Curvytron (JavaScript, MIT, mature, inactive since 2015)
- CuteMaze (C++, GPL-3.0, mature)
- Cuyo (C++, OCaml, GPL-2.0, mature, inactive since 2014)
- Cytadela (C++, GPL-3.0, beta, inactive since 2013)
- Cytopia (C++, GPL-3.0, beta)
- D2X-XL (C++, Custom, GPL-2.0, mature, inactive since 2015)
- Daedalus (C++, GPL-2.0, mature, inactive since 2018)
- Daggerfall Unity (C#, MIT, mature)
- Dagon (D, Boost-1.0, beta)
- Daimonin (C, GPL-2.0, mature)
- Danger from the Deep (C++, C, GPL-2.0, beta, inactive since 2011)
- Dangerous Dave 2: Modification Edition (C++, MIT, mature)
- Dark Destiny (Java, JavaScript, ?, mature, inactive since 2016)
- Dark Oberon (C++, C, Objective-C, GPL-2.0, mature, inactive since 2009)
- DarkCity (PHP, GPL-3.0, mature, inactive since 2012)
- Darkflame Universe (C++, AGPL-3.0, mature)
- DarkFO (TypeScript, JavaScript, Python, Apache-2.0, beta, inactive since 2019)
- DarkPlaces (C, GPL-2.0, mature, inactive since 2014)
- Data Storm (C, Apache-2.0, mature, inactive since 2017)
- Dave Gnukem (C++, GPL-2.0, mature)
- Dawn (C++, Lua, GPL-3.0, beta, inactive since 2011)
- DDraceNetwork (C, C++, zlib, mature)
- Deathchase 3D (C, Perl, Script, GPL-2.0, mature, inactive since 2002)
- Deathlord Relorded (C, C++, AGPL-3.0, mature)
- Decker (Java, GPL-2.0, beta, inactive since 2013)
- Deer Portal (C++, zlib, beta)
- Defendguin (C, GPL-2.0, mature, inactive since 2009)
- Defendo (GDScript, PHP, GPL-3.0, mature, inactive since 2018)
- Deflektor X4 (C, Custom, mature, inactive since 2008)
- Delaford (JavaScript, PHP, MIT, beta)
- Deliantra (C, Perl, C++, GPL-2.0, mature)
- DelverEngine (Java, Custom, mature)
- DemiGod (Java, GPL-3.0, beta, inactive since 2013)
- Der Clou! (C, Custom, beta, inactive since 2017)
- DesktopAdventures (C, LGPL-2.1, beta)
- Destination Sol (Java, Apache-2.0, mature)
- Dethrace (C, GPL-3.0, beta)
- Devana (PHP, zlib, beta)
- Devilution (C, C++, Unlicense, mature)
- DevilutionX (C, C++, Unlicense, mature)
- DGEngine (C++, zlib, GPL-3.0, beta)
- dhewm3 (C, C++, GPL-3.0, mature)
- Diablerie (C#, MIT, beta)
- diablo-js (Java, JavaScript, MIT, mature)
- Diabolika (C++, zlib, mature)
- Digbuild (C, C++, GPL-2.0, beta, inactive since 2011)
- Digger Remastered (C, GPL-2.0, mature, inactive since 2004)
- Digital: A Love Story (Ren'Py, Python, CC-BY-NC-SA-3.0, mature)
- dim3 (C, MIT, beta, inactive since 2014)
- Dingo-Engine (Java, 3-clause BSD, beta, inactive since 2016)
- Dink Smallwood HD (C, Custom, mature)
- DirectX12GameEngine (C#, MIT, beta)
- Divercity (Java, GPL-3.0, beta, inactive since 2015)
- Dmomd (Lisp, GPL-3.0, mature)
- DNT (C++, GPL-3.0, beta, inactive since 2016)
- Do It Yourself Doom With SDL (C++, MIT, beta)
- Dodge (Java, GPL-3.0, mature, inactive since 2012)
- Domination (Java, GPL-3.0, mature)
- Domino On Acid (Java, GPL-2.0, mature, inactive since 2009)
- donut (C, C++, GPL-3.0, beta)
- Doom Legacy (C++, GPL-2.0, mature)
- DOOM Retro (C, C++, GPL-3.0, mature)
- DOOM-iOS (C++, C, GPL-2.0, mature, inactive since 2012)
- Doom64EX (C, C++, GPL-2.0, mature)
- DOOM (C, Custom, mature, inactive since 2012)
- Doomsday Engine (C, C++, GPL-2.0, GPL-3.0, LGPL-3.0, mature)
- Dope Wars (C, GPL-2.0, mature, inactive since 2013)
- doukutsu-rs (Rust, MIT, beta)
- Dragon History - Dračí Historie (Pascal, Script, Pascal, Assembly, GPL-2.0, mature, inactive since 2010)
- Dragon Hunt (Python, GPL-2.0, mature)
- dRally (Assembly, C, MIT, beta)
- DreamChess (C, GPL-3.0, beta)
- DreamZZT (C, C++, GPL-2.0, beta, inactive since 2007)
- Dreerally (C, C++, Custom, beta)
- DRL (Lua, Pascal, GPL-2.0, mature)
- DroidZebra (C, Java, GPL-3.0, mature, inactive since 2015)
- Dstroy (C++, GPL-2.0, mature, inactive since 2009)
- Duality (C#, MIT, mature)
- Duck Hunt JS (JavaScript, MIT, mature)
- Duck Marines (Lua, zlib, mature, inactive since 2016)
- Duck Rehunt (Python, GPL-3.0, beta, inactive since 2011)
- Duckmaze (Python, GPL-2.0, beta)
- Duel Commander (C, GPL-3.0, beta, inactive since 2009)
- DUGA (Python, MPL-2.0, beta, inactive since 2018)
- Duke 2 Reconstructed (C, GPL-2.0, mature)
- Duke3D (C, GPL-2.0, beta, inactive since 2009)
- Duke3d_w32 (C, GPL-2.0, beta, inactive since 2008)
- DukeGDX (Java, GPL-3.0, beta)
- Dune Dynasty (C, C++, GPL-2.0, mature, inactive since 2014)
- Dune II - The Maker (Java, MIT, beta, inactive since 2020)
- Dune Legacy (C++, GPL-2.0, mature)
- Dungeon Craft (C++, GPL-2.0, mature)
- Dungeon Crawl Stone Soup (C++, Lua, GPL-2.0, mature)
- Dungeon Eye (C#, GPL-3.0, beta, inactive since 2016)
- Dungeon Hero (Java, MIT, mature)
- Dungeon Monkey Eternal (Python, GPL-2.0, mature, inactive since 2016)
- Dungeon Monkey Unlimited (Pascal, LGPL-2.1, mature, inactive since 2010)
- Dungeon of Quake (Odin, Pascal, MIT, Unlicense, beta)
- Dungeon Quest (Java, MIT, mature)
- Dungeon (Java, 3-clause BSD, mature)
- Dunnet (Emacs Lisp, GPL-3.0, mature, inactive since 1992)
- Dust Racing 2D (C, C++, GPL-3.0, mature)
- DwarfCorp (C#, MIT, mature)
- DXX-Rebirth (C, C++, Python, GPL-3.0, Custom, mature)
- DynaDungeons (GDScript, GPL-3.0, beta, inactive since 2018)
- eAdventure (Java, C#, GPL-3.0, mature, inactive since 2014)
- Earth 2140 on OpenRA (C#, GPL-3.0, beta)
- Eat The Whistle (C, ?, mature, inactive since 2017)
- Eboard (C++, GPL-2.0, mature)
- Ecksdee (C++, GPL-2.0, beta, inactive since 2009)
- ECWolf (C++, GPL-2.0, LGPL-2.1, zlib, MIT, IJG, Public domain, mature)
- EDGE (C++, C, GPL-2.0, mature)
- EDuke32 (C, C++, GPL-2.0, mature)
- Egoboo (C++, C, GPL-3.0, mature, inactive since 2015)
- Einstein Puzzle (C++, GPL-2.0, mature, inactive since 2005)
- EliFUT Android (Java, Kotlin, Apache-2.0, mature)
- Elite remake (C, 3-clause BSD, mature, inactive since 2008)
- ElonaFoobar (C++, Lua, MIT, mature)
- Elysium Engine (C, GPL-2.0, beta, inactive since 2006)
- Emilia Pinball (C++, GPL-2.0, beta)
- Empty Clip (C++, GPL-2.0, mature)
- EmptyEpsilon (C, C++, Lua, GPL-2.0, mature)
- Enchanted Fortress (Java, LGPL-3.0, mature)
- Endgame: Singularity (Python, GPL-2.0, beta)
- Endless Sky (C++, GPL-3.0, mature)
- Enduro tribute (JavaScript, MIT, mature)
- engge (C++, MIT, beta)
- Enigma (C, C++, GPL-2.0, mature)
- EnTT Pacman (C, C++, MIT, mature)
- Eos, Dawn of Light: A Space Opera (Python, MIT, beta, inactive since 2007)
- Epiar (C, C++, Lua, GPL-2.0, beta)
- EPOH (JavaScript, MIT, beta)
- erampage (C, GPL-2.0, beta, inactive since 2015)
- Erebus (C++, GPL-3.0, beta)
- Escape Towards The Unknown (C, GPL-2.0, beta, inactive since 2016)
- Esenthel Engine (C, C++, Custom, beta)
- ET: Legacy (C, C++, Lua, GPL-3.0, mature)
- Eternal Lands (C, C++, Custom, mature)
- EternalWinterWars (Java, MIT, beta, inactive since 2014)
- Etterna (C, C++, Lua, MIT, beta)
- Evil Cult (Haxe, JavaScript, GPL-3.0, mature)
- excalibur (TypeScript, 2-clause BSD, beta)
- Excellent Bifurcation (C, GPL-2.0, mature, inactive since 2007)
- Executive Man (JavaScript, Custom, mature, inactive since 2017)
- Exolon (JavaScript, MIT, mature)
- Extreme Tux Racer (C++, GPL-2.0, beta, inactive since 2018)
- Exult (C++, GPL-2.0, mature)
- ezEngine (C++, JavaScript, MIT, mature)
- ezQuake (C, C++, GPL-2.0, mature)
- F-1 Spirit (C++, ?, beta, inactive since 2009)
- Fairy-Max (C, Custom, mature, inactive since 2018)
- Falcon's Eye (C, NetHack General Public License, mature, inactive since 2004)
- Fall of Imiryn (C++, Python, GPL-3.0, beta, inactive since 2009)
- Fallen Spire (Python, GPL-3.0, beta, inactive since 2009)
- Falling Time (C, C++, GPL-2.0, mature)
- Fallout 2 Community Edition (C++, Custom, mature)
- Falltergeist (C++, GPL-3.0, beta)
- Fanwor (C, GPL-2.0, mature)
- FAR Colony (Pascal, GPL-3.0, beta, inactive since 2014)
- Faur (C, Python, C++, GPL-3.0, beta)
- Fictional Air Combat (C, C++, GPL-3.0, beta, inactive since 2012)
- FIFE (C++, Python, LGPL-2.1, beta)
- Fire Madness (Pascal, GPL-3.0, mature, inactive since 2016)
- Fire Strike Retro (Java, Haxe, JavaScript, Ruby, PHP, MIT, mature)
- First Strike (Java, MIT, mature, inactive since 2018)
- Fish Fillets - Next Generation (C++, GPL-2.0, mature)
- Fish Rings for Android (Java, GPL-3.0, mature, inactive since 2015)
- Fitzquake (C, GPL-2.0, beta, inactive since 2009)
- Flappy Cow (Java, MIT, mature)
- Flex Engine (C++, MIT, beta)
- FlightGear (C++, GPL-2.0, mature)
- FLTK Recycling Game! (C++, LGPL-2.1, mature, inactive since 2014)
- FLTrator (C++, GPL-3.0, mature, inactive since 2016)
- Fluid Table Tennis (JavaScript, MIT, mature, inactive since 2013)
- Flukz (C++, GPL-2.0, beta, inactive since 2014)
- FOnline (C, C++, C#, GPL-3.0, beta)
- FooBillard++ (C, GPL-2.0, mature, inactive since 2012)
- FooBillard (C, GPL-2.0, mature, inactive since 2010)
- Forge (Java, GPL-3.0, mature)
- Forsaken (C, C++, GPL-2.0, Proprietary, beta, inactive since 2013)
- Foursies (Elm, JavaScript, GPL-3.0, mature, inactive since 2016)
- Foxy Misfortunes (Pascal, GPL-3.0, mature)
- FQuake3 (F#, C, GPL-2.0, beta, inactive since 2014)
- fRaBs (Lisp, C++, C, Public domain, mature, inactive since 2016)
- Fractal Engine (C++, MIT, mature)
- Free Allegiance (C++, MIT, mature)
- Free Heroes 2 (C++, GPL-2.0, beta, inactive since 2015)
- Free in the Dark (engine) (C, C++, GPL-2.0, beta)
- Free Mars (Java, GPL-3.0, mature)
- Free Space Colonization (C, GPL-2.0, beta, inactive since 2017)
- Free Tennis (OCaml, GPL-2.0, beta, inactive since 2005)
- freeablo (C++, GPL-3.0, beta)
- freeaoe (C++, GPL-3.0, beta)
- FreeBlocks (C, Java, GPL-3.0, beta, inactive since 2015)
- Freebloks 3D for Android (Kotlin, C++, GPL-2.0, mature)
- Freeciv Alpha Centauri project (C, GPL-2.0, beta, inactive since 2003)
- Freeciv-web (JavaScript, Java, Python, AGPL-3.0, mature)
- Freeciv (C, GPL-2.0, mature)
- FreeCol (Java, GPL-2.0, mature)
- FreeCS (QuakeC, GPL-2.0, mature)
- Freedoom (None, Python, None, beta)
- FreedroidRPG (C, C++, Lua, GPL-2.0, mature)
- FrEee (C#, CC-BY-NC-SA-2.0, beta)
- FreeFalcon (C, C++, 2-clause BSD, inactive since 2014)
- FreeGemas (C++, GPL-2.0, mature)
- freegish (C, GPL-2.0, beta, inactive since 2017)
- FreeHeroes (C++, MIT, beta)
- FreeHL (C, C++, ISC, beta)
- Freekick 3 (C++, Python, GPL-3.0, mature, inactive since 2015)
- FreeLords (Java, GPL-2.0, beta, inactive since 2017)
- Freeminer (C++, Lua, GPL-3.0, beta)
- Freenukum (C, GPL-3.0, beta, inactive since 2009)
- FreeOrion (C++, Python, GPL-2.0, beta)
- FreePrince (C, GPL-2.0, beta, inactive since 2011)
- FreeRails (Java, C++, GPL-2.0, beta, inactive since 2008)
- FreeRCT (C++, GPL-2.0, beta, inactive since 2016)
- Freeserf.net (C#, GPL-3.0, mature)
- Freeserf (C, C++, GPL-3.0, mature)
- FreeSiege (C++, GPL-3.0, beta)
- FreeSims (C#, MPL-2.0, beta)
- FreeSO (C#, MPL-2.0, beta)
- FreeSpace 2 Source Code Project (C, C++, Unlicense, mature)
- Freestars (C++, GPL-2.0, beta, inactive since 2008)
- FreeSynd (C++, GPL-2.0, beta, inactive since 2017)
- FreeTrain (C#, C++, LGPL-2.1, beta, inactive since 2009)
- freeVikings (Ruby, GPL-2.0, beta)
- Frets on Fire X (Python, GPL-2.0, mature)
- Frets on Fire (Python, GPL-2.0, mature, inactive since 2008)
- Freya Game Engine (Java, LGPL-2.1, beta, inactive since 2002)
- Friking Shark (C++, C, GPL-3.0, mature)
- Froggix (Python, GPL-3.0, beta, inactive since 2009)
- Frozen Bubble (Perl, C++, GPL-2.0, mature, inactive since 2012)
- FTEQW (C, GPL-2.0, mature)
- Fujo (Python, CC-BY-SA-4.0, mature, inactive since 2014)
- FunLabyrinthe (Pascal, GPL-2.0, mature, inactive since 2012)
- Fusee (C#, Python, MIT, beta)
- Future Cop: MIT (C++, C, MIT, beta)
- Galaxy Forces V2 (C++, Public domain, mature)
- GalaxyMage Redux (Python, GPL-2.0, beta, inactive since 2011)
- GalaxyNG (C, PHP, Script, GPL-2.0, mature, inactive since 2005)
- GameCake (C, C++, Lua, MIT, mature)
- gamekit (C++, C, zlib, mature, inactive since 2015)
- GameLV (C++, GPL-2.0, beta)
- GamePlay (C++, C, Apache-2.0, mature, inactive since 2016)
- Gang Garrison 2 (Game Maker Script, MPL-2.0, mature)
- Garith (C++, Perl, LGPL-2.1, mature, inactive since 2013)
- GCompris (C, Python, GPL-3.0, mature)
- GDash (C++, MIT, beta)
- GDHexGrid (GDScript, MIT, mature)
- GearHead 2 (Pascal, LGPL-2.0, beta)
- GearHead (Pascal, LGPL-2.1, Apache-2.0, mature)
- Gee Whiz (C, Script, GPL-2.0, beta, inactive since 2004)
- Gem Drop X (C, GPL-2.0, beta, inactive since 2002)
- ges-code (C, C++, GPL-3.0, mature)
- Ghostly (C++, GPL-3.0, mature, inactive since 2016)
- Gift Grabber (JavaScript, Apache-2.0, mature)
- Gigalomania (C++, GPL-2.0, mature)
- Gilbert and the doors (C, GPL-3.0, mature, inactive since 2018)
- Gish (C, GPL-2.0, mature, inactive since 2010)
- gist-txt (JavaScript, MIT, mature, inactive since 2018)
- GJID (C++, MIT, mature, inactive since 2017)
- GL TRON (Java, GPL-3.0, mature, inactive since 2012)
- GL-117 (C++, GPL-2.0, mature, inactive since 2005)
- Glest (C++, Script, GPL-2.0, mature, inactive since 2009)
- GLKeeper (GrimLands Keeper) (C++, MIT, beta, inactive since 2020)
- Globulation 2 (C++, GPL-3.0, mature)
- Gloomy Dungeons 2 (Java, MIT, mature)
- Gloomy Dungeons (Java, MIT, mature, inactive since 2018)
- glParchis (Python, GPL-3.0, mature)
- glPortal (C++, zlib, beta)
- GLSpeed (Pascal, C, GPL-2.0, mature)
- GLtron (C, ?, beta, inactive since 2017)
- GLXY (Java, Apache-2.0, mature)
- Gnome Chess (Vala, GPL-3.0, mature)
- Gnome Hearts (Python, GPL-2.0, mature, inactive since 2015)
- Gnomescroll (C, C++, Python, GPL-3.0, beta, inactive since 2013)
- GNU Chess (C++, GPL-3.0, mature, inactive since 2017)
- GNU FreeDink (C, GPL-3.0, mature, inactive since 2012)
- GNU Go (C, GPL-3.0, mature, inactive since 2011)
- GNU Shogi (C, GPL-3.0, mature, inactive since 2018)
- Go Ollie! (?, GPL-3.0, mature, inactive since 2011)
- Goblin Camp (C++, Python, GPL-3.0, beta, inactive since 2012)
- Goblin Hack (C++, GPL-2.0, beta, inactive since 2009)
- Godot Card Game Framework (GDScript, AGPL-3.0, mature)
- Gods Deluxe (Java, MIT, mature, inactive since 2020)
- GoldenEye: Source (C++, C, GPL-3.0, mature, inactive since 2018)
- Golly (C++, Java, GPL-2.0, mature)
- Gorc (C++, Apache-2.0, beta)
- Gorillas-rs (Rust, MIT, beta)
- Gorillas (Objective-C, JavaScript, Java Research License, mature, inactive since 2014)
- Gottet (C++, GPL-3.0, mature)
- GPL Arcade Volleyball (C++, GPL-2.0, beta, inactive since 2006)
- Grail (C++, Lua, GPL-3.0, beta, inactive since 2013)
- Granatier (C++, GPL-2.0, mature)
- Gravitation (C++, Public domain, mature, inactive since 2008)
- Gravity Defied (Java, GPL-2.0, mature, inactive since 2015)
- Greenius' Civil War (C++, C, GPL-2.0, beta, inactive since 2001)
- Griefly (C++, Go, Python, MIT, beta)
- Grimsonland (JavaScript, TypeScript, MIT, mature, inactive since 2017)
- Grobots (C++, GPL-2.0, mature, inactive since 2014)
- gta2net (C#, MIT, beta, inactive since 2017)
- GUSANOS (C++, GPL-2.0, beta, inactive since 2006)
- Gusty's Serpents (C++, GPL-3.0, beta, inactive since 2014)
- Gweled (C, Script, GPL-2.0, mature)
- GZDoom (C, C++, GPL-3.0, mature)
- H-Craft Championship (C++, C, zlib, mature, inactive since 2015)
- Hack (C, 3-clause BSD, mature, inactive since 1985)
- Hale (Java, GPL-2.0, beta, inactive since 2014)
- halley (C, C++, Apache-2.0, beta)
- Hammer of Thyrion (C, GPL-2.0, mature)
- Hardwar (C++, GPL-3.0, beta, inactive since 2015)
- Harmonist: Dayoriah Clan Infiltration (Go, ISC, beta)
- Harris (C, Python, GPL-3.0, beta)
- Harvest Moon 2.0 (GDScript, MIT, beta, inactive since 2020)
- Hase (C, GPL-3.0, beta)
- Haxima (C++, GPL-3.0, beta)
- Head over Heels (C++, GPL-3.0, mature)
- Heart of the Alien (C, GPL-2.0, beta, inactive since 2005)
- Hedgewars (Lua, C, C++, Pascal, Haskell, GPL-2.0, mature)
- Help Hannah's Horse (C++, GPL-2.0, beta, inactive since 2008)
- Hematite (Rust, MIT, beta)
- Hero of Allacrost (C++, Lua, GPL-2.0, mature)
- Heroes of Civilizations (C++, C#, GPL-2.0, beta)
- Heroes of Wesnoth (C++, GPL-3.0, beta, inactive since 2010)
- Heroes of Wing Commander (Python, GPL-3.0, beta, inactive since 2014)
- Heroine Dusk (JavaScript, GPL-3.0, mature, inactive since 2017)
- Hex Game (C++, MIT, beta)
- Hex-a-hop (C++, GPL-2.0, mature, inactive since 2013)
- HexGL (JavaScript, CoffeeScript, MIT, mature, inactive since 2016)
- heXon (C++, GPL-2.0, beta)
- Hexoshi (Python, GPL-3.0, beta, inactive since 2016)
- Hextris (JavaScript, GPL-3.0, mature)
- Hexwar (Ruby, JavaScript, MIT, beta, inactive since 2012)
- HGE (C, Haskell, zlib, beta, inactive since 2013)
- HHexen (C, GPL-2.0, mature, inactive since 2013)
- Hnefatafl (C, ISC, beta, inactive since 2014)
- Hocoslamfy (C, C++, GPL-2.0, beta, inactive since 2016)
- HoDoKu (Java, GPL-3.0, mature, inactive since 2013)
- Holtz (C++, GPL-2.0, mature)
- HolySpirit (C++, Haskell, GPL-3.0, beta, inactive since 2013)
- Honey Town (C#, GPL-3.0, beta, inactive since 2020)
- Hopson-Arcade (C++, GPL-3.0, mature)
- HoverRace (C++, Custom, mature, inactive since 2016)
- Hovertank 3D (C++, Assembly, GPL-2.0, mature, inactive since 2014)
- HTML5 Pacman (JavaScript, WTFPL, mature, inactive since 2013)
- Hurrican (C++, MIT, mature)
- Hypatia (Python, MIT, beta, inactive since 2016)
- Hypercube (Java, GPL-2.0, mature, inactive since 2016)
- HyperRogue (C++, GPL-2.0, mature)
- I Have No Tomatoes (C++, zlib, mature, inactive since 2004)
- ICBM3D (C, ?, beta, inactive since 1998)
- Ice Breaker (C, GPL-2.0, mature, inactive since 2003)
- Iceball (C, Lua, GPL-3.0, inactive since 2017)
- iiChantra (C++, MIT, beta, inactive since 2012)
- ika (C++, Python, PHP, C#, GPL-2.0, beta, inactive since 2007)
- Ilarion (C++, Java, Lua, GPL-3.0, mature)
- Illarion (C++, Java, Lua, AGPL-3.0, GPL-3.0, mature)
- IMaze (C, 4-clause BSD, mature, inactive since 2001)
- Imperium (?, ?, mature)
- Inertia Blast (C, GPL-2.0, mature)
- Inexor (C++, JavaScript, zlib, beta, inactive since 2018)
- Infiniminer (C#, MIT, mature, inactive since 2016)
- Infinite Mario Bros (Java, 3-clause BSD, mature, inactive since 2010)
- Infinite Tux (Java, GPL-3.0, Public domain, mature)
- Infon Battle Arena (C, Lua, GPL-2.0, beta, inactive since 2012)
- Innocence Engine (C++, GPL-3.0, beta)
- INSTEAD (C, Lua, Java, MIT, mature)
- Intersect (C#, MIT, GPL-2.0, beta)
- Intricacy (Haskell, GPL-3.0, beta)
- IO Reboot (C#, MIT, mature, inactive since 2017)
- ioquake3 (C, GPL-2.0, mature)
- iortcw (C, C++, GPL-3.0, mature)
- Iris2 (C, C++, Lua, GPL-3.0, beta, inactive since 2017)
- Ironseed (Pascal, GPL-3.0, mature, inactive since 2013)
- irrlamb (C, C++, GPL-3.0, mature)
- Isleward (JavaScript, AGPL-3.0, mature)
- Isogenic Game Engine (JavaScript, MIT, mature)
- Isolmoa (JavaScript, Java, GPL-3.0, mature, inactive since 2014)
- Isometric Turn-Based Strategy (Python, MIT, beta)
- Isometric-Minesweeper (Python, MIT, beta)
- Iter Vehemens ad Necem (C++, GPL-2.0, beta)
- Ithaka Board Game (Java, GPL-3.0, mature)
- Jactorio (C++, MIT, beta)
- Jagged Alliance 2 Stracciatella (C, C++, Custom, mature)
- Jake2 (Java, GPL-2.0, beta, inactive since 2006)
- Jamp (C++, GPL-3.0, beta, inactive since 2009)
- JavaScript Graphic Adventure Maker (JavaScript, MIT, mature)
- javascript-E.T. (JavaScript, Assembly, MIT, beta, inactive since 2017)
- Javelin (Java, GPL-2.0, mature, inactive since 2016)
- Jazz² Resurrection (C#, JavaScript, GPL-3.0, mature)
- jClassicRPG (Java, LGPL-3.0, beta, inactive since 2010)
- JediAcademyLinux (C++, GPL-2.0, beta, inactive since 2017)
- JediOutcastLinux (C, C++, GPL-2.0, mature)
- Jet-Story (Assembly, C, C++, MIT, beta)
- JetPac (C#, MIT, mature, inactive since 2015)
- jewelthief (Java, GPL-3.0, mature, inactive since 2016)
- JFDuke3D (C, GPL-2.0, beta, inactive since 2005)
- JGame (Java, 3-clause BSD, mature, inactive since 2012)
- JonoF's Shadow Warrior Port (JFSW) (C, GPL-2.0, beta, inactive since 2005)
- JQuest (Java, GPL-2.0, beta, inactive since 2006)
- JSettlers (Java, GPL-3.0, mature)
- jsFO (JavaScript, Python, Apache-2.0, beta, inactive since 2017)
- JSkat (Java, GPL-3.0, Apache-2.0, beta)
- JSoko (Java, GPL-3.0, mature)
- Julius (C, C++, AGPL-3.0, mature)
- Jump Don't Die (Java, GPL-3.0, mature)
- Jump'n'Bump (C, GPL-2.0, mature, inactive since 2004)
- Just another Tetris™ clone (Java, WTFPL, mature, inactive since 2017)
- Kai ‘Opua (JavaScript, MIT, mature, inactive since 2013)
- KaM Remake (Pascal, AGPL-3.0, mature)
- Kartering (C, GPL-2.0, MIT, ISC, beta, inactive since 2015)
- KAtomic (C++, GPL-2.0, mature)
- Keen Dreams (C, Assembly, C++, GPL-2.0, mature, inactive since 2014)
- KeeperFX (C, C++, GPL-2.0, beta)
- KeeperRL (C, C++, GPL-2.0, beta)
- Key Runner (C++, Script, GPL-3.0, mature, inactive since 2013)
- KGoldrunner (C++, GPL-2.0, mature)
- kiki the nano bot (C++, Public domain, mature, inactive since 2007)
- Killer Crates (Java, MIT, beta, inactive since 2017)
- Kingdoms (C++, GPL-3.0, beta, inactive since 2014)
- KittenMaxit (Java, MIT, beta)
- Kiwi.js (JavaScript, TypeScript, MIT, mature, inactive since 2015)
- KlayGE (C++, GPL-2.0, mature)
- Klooni 1010! (Java, GPL-3.0, beta)
- KMines (C++, GPL-2.0, mature)
- KnightOfWor (Java, GPL-3.0, beta, inactive since 2015)
- Knights (C++, GPL-3.0, beta, inactive since 2014)
- Kobo Deluxe (C++, GPL-2.0, beta, inactive since 2007)
- Kobold's Quest 2 (Python, LGPL-3.0, beta, inactive since 2011)
- Koi Farm (JavaScript, Custom, mature)
- Kolf (C, GPL-2.0, mature)
- Korax' Heritage (None, ?, mature)
- KQ Lives (C, GPL-2.0, beta, inactive since 2011)
- Krank (Python, Public domain, beta, inactive since 2008)
- KRaptor (C, MIT, beta, inactive since 2004)
- Kroz (Pascal, GPL-2.0, mature, inactive since 1990)
- Kryftolike (Pascal, GPL-3.0, mature)
- Krystal Drop (C++, GPL-2.0, beta, inactive since 2004)
- KSnakeDuel (C++, GPL-2.0, mature)
- Ksudoku (C++, GPL-2.0, mature)
- Kuklomenos (C++, GPL-3.0, beta, inactive since 2012)
- KungFoo Barracuda (C++, GPL-3.0, mature, inactive since 2016)
- L'Abbaye des Morts (C, GPL-3.0, mature, inactive since 2018)
- l-echo (C++, GPL-3.0, beta, inactive since 2016)
- LAB3D/SDL (ktpanda) (C, Custom, mature, inactive since 2015)
- LAB3D/SDL (C, Custom, mature, inactive since 2013)
- Labyrinth of Worlds (C++, LGPL-3.0, beta, inactive since 2010)
- ladder (Go, MIT, beta, inactive since 2016)
- Ladder (Java, GPL-2.0, mature, inactive since 2005)
- LambdaHack (Haskell, 3-clause BSD, beta)
- LambdaRogue: The Book of Stars (Pascal, GPL-2.0, mature, inactive since 2012)
- Land of Fire (Script, PHP, GPL-2.0, beta)
- Laser Kombat (C++, GPL-3.0, mature)
- LastTry (Java, MIT, beta, inactive since 2017)
- LBA2 Remake (TypeScript, MIT, beta)
- LBreakout2 (C, GPL-2.0, mature, inactive since 2010)
- LBreakoutHD (C++, GPL-3.0, mature)
- LegionGame (C#, GPL-3.0, beta)
- Lemmings.ts (TypeScript, MIT, mature)
- Lemmini (Java, Apache-2.0, beta, inactive since 2017)
- LevelHead (C++, Python, GPL-3.0, mature, inactive since 2009)
- Lexica (Java, GPL-3.0, mature)
- LGames (C++, GPL-2.0, mature)
- LGeneral (C, GPL-2.0, mature, inactive since 2017)
- Liberal Crime Squad (C++, GPL-2.0, mature, inactive since 2012)
- Liberation Circuit (C, GPL-3.0, mature)
- Liblast (GDScript, AGPL-3.0, beta)
- Libre Pinball (GDScript, MIT, beta, inactive since 2015)
- Librelancer (C, C#, MIT, beta)
- LibreMines (C++, GPL-3.0, mature)
- LibreQuake (Python, 3-clause BSD, beta)
- Librerama (GDScript, GPL-3.0, mature)
- LieroLibre (C++, 2-clause BSD, mature, inactive since 2017)
- Limbs Off (C++, GPL-3.0, beta, inactive since 2013)
- LimonEngine (C, C++, LGPL-3.0, beta)
- LinCity-NG (C++, GPL-2.0, mature)
- Lincity (C, GPL-2.0, mature, inactive since 2005)
- Linley's Dungeon Crawl (C, C++, Custom, mature, inactive since 2006)
- Linwarrior 3D (C++, Apache-2.0, mature, inactive since 2010)
- LionEngine (Java, GPL-3.0, mature)
- Lionheart Remake (Java, GPL-3.0, beta, inactive since 2018)
- Lips of Suna (C, Lua, C++, GPL-3.0, beta, inactive since 2014)
- Liquid War (C, Script, GPL-3.0, mature, inactive since 2015)
- Liquid Wars (C++, Java, GPL-3.0, mature, inactive since 2014)
- LITIENGINE (Java, MIT, beta)
- Little Big Adventure 1 - Engine source code (Assembly, C, GPL-2.0, beta)
- Little Big Adventure 2 - Engine source code (Assembly, C++, GPL-2.0, beta)
- Lix (D, C++, CC0, beta)
- LMarbles (C, GPL-2.0, beta)
- Lode Runner 2020 (C++, C, Java, MIT, mature)
- Lona (Java, JavaScript, GPL-3.0, mature)
- Lords of the Fey (JavaScript, AGPL-3.0, beta, inactive since 2018)
- LordsAWar! (C++, GPL-3.0, mature)
- Lose Your Marbles (JavaScript, MIT, mature, inactive since 2014)
- LOZ (C++, C#, Apache-2.0, beta)
- LPairs (C++, GPL-3.0, mature, inactive since 2021)
- LTris (C, GPL-2.0, mature, inactive since 2013)
- lttp-phaser (TypeScript, JavaScript, MIT, beta, inactive since 2016)
- Lugaru (C++, GPL-2.0, mature)
- Lumos Engine (C++, MIT, beta)
- Luola (C, GPL-2.0, mature, inactive since 2005)
- LZWolf (C++, 3-clause BSD, mature)
- M.A.R.S. (C++, C, GPL-3.0, beta, inactive since 2016)
- M.E.W.L. (C++, GPL-2.0, beta, inactive since 2015)
- Machinations (C++, C, GPL-2.0, beta, inactive since 2003)
- Maelstrom (C, C++, GPL-2.0, mature, inactive since 2002)
- MafiaUnity (C#, Apache-2.0, beta, inactive since 2020)
- Magarena (Java, Groovy, GPL-3.0, mature)
- MAGE - Matthias Advanced Game Engine (C++, GPL-3.0, beta)
- Magic Gardeners Tournament (Python, GPL-2.0, beta, inactive since 2007)
- Magical Life (C#, MIT, beta)
- Magnetar (C, C++, MIT, beta)
- Mah-Jong (C, GPL-2.0, mature)
- ManaPlus (C++, GPL-3.0, mature)
- Manic Digger (C#, Public domain, Unlicense, mature, inactive since 2017)
- Marble Madness 3d (C++, LGPL-2.1, beta, inactive since 2012)
- Marble Marcher (C++, GPL-2.0, mature)
- Marblez (C#, MIT, beta, inactive since 2017)
- Mari0 (Lua, MIT, mature, inactive since 2012)
- Mario Objects (C#, MIT, beta)
- Mars, Land of No Mercy (C++, GPL-2.0, beta, inactive since 2008)
- Maxit (C++, 3-clause BSD, mature, inactive since 2014)
- Mazer (Pascal, GPL-3.0, beta, inactive since 2018)
- mc2 (C++, GPL-3.0, beta)
- Me and My Shadow (C++, GPL-3.0, beta)
- Mechanized Assault & eXploration Reloaded (C++, C, GPL-2.0, beta)
- MechCommander 2 Omnitech (C++, MS-PL, beta, inactive since 2013)
- Mega Mario (C++, LGPL-2.1, mature, inactive since 2012)
- MegaGlest (C, C++, GPL-3.0, mature)
- MegaMek (Java, GPL-2.0, mature)
- MekWars (Java, GPL-2.0, mature)
- melonJS (JavaScript, MIT, mature)
- Memory Game (Java, Apache-2.0, mature)
- Mercenary Commander (Java, 3-clause BSD, beta, inactive since 2010)
- Meridian 59 (C++, C, GPL-2.0, mature)
- Meritous (C, C++, GPL-3.0, mature, inactive since 2008)
- Metaforce (C, C++, MIT, beta)
- Metal Mech (PHP, GPL-2.0, beta, inactive since 2006)
- Metar Sweeper (Pascal, GPL-3.0, beta, inactive since 2015)
- Mice Men: Remix (Java, LGPL-3.0, mature, inactive since 2016)
- Micropolis (C++, Java, Python, GPL-3.0, mature, inactive since 2015)
- micropolisJS (JavaScript, GPL-3.0, mature)
- Microracers (C, C++, GPL-2.0, beta, inactive since 2005)
- MicroWar 2.0 (Python, 3-clause BSD, mature, inactive since 2009)
- Mighty Knight (PHP, GDScript, MIT, mature, inactive since 2018)
- Mindustry (Java, GPL-3.0, mature)
- MineClone 2 (Lua, GPL-3.0, beta)
- MineCraft-One-Week-Challenge (C++, C, MIT, beta)
- minecraft-weekend (C, MIT, beta)
- Minecraft (C++, C, MIT, beta)
- Mines (Vala, GPL-3.0, mature)
- Minesweeper (in C) (C, 3-clause BSD, beta, inactive since 2015)
- minesweeper-rs (Rust, MIT, mature)
- Minesweeper.Zone (JavaScript, PHP, MIT, mature)
- Minetest Game (Lua, LGPL-2.1, mature)
- mini2Dx (Java, C#, Apache-2.0, mature)
- Minilens (GDScript, GPL-3.0, mature, inactive since 2018)
- Minima (Lua, GPL-3.0, mature)
- Mininim (C, GPL-3.0, beta, inactive since 2017)
- MiniPacman (Ada, GPL-3.0, mature)
- Minos (Java, GPL-3.0, mature)
- Mirror Magic (C, GPL-2.0, mature)
- mk.js (JavaScript, MIT, beta)
- Mmpong (C, GPL-3.0, beta, inactive since 2009)
- Moagg2 (Java, GPL-2.0, mature, inactive since 2008)
- Mocha Doom (Java, GPL-3.0, beta, inactive since 2012)
- Mojotron: Robot Wars (C++, GPL-2.0, mature, inactive since 2019)
- Monofoxe (C#, MIT, mature)
- Monsters and Mushrooms (Python, GPL-2.0, mature, inactive since 2010)
- Monsterz (Python, WTFPL, beta, inactive since 2007)
- Monstrosity (Python, MIT, mature)
- Monty Mole PC remake (C++, GPL-2.0, mature, inactive since 2012)
- Moon-buggy (C, GPL-2.0, mature, inactive since 2006)
- Moonbase Assault (Java, MIT, beta, inactive since 2019)
- Mop(e)snake (Python, GPL-2.0, beta, inactive since 2009)
- Morpheus Web Remake (JavaScript, TypeScript, MIT, beta)
- Moubootaur Legends (C, C++, Script, GPL-3.0, beta)
- movbizz (PHP, JavaScript, MIT, beta, inactive since 2015)
- MoveNoid (C++, GPL-3.0, 3-clause BSD, mature, inactive since 2017)
- Mpango (Java, JavaScript, GPL-2.0, beta, inactive since 2013)
- Mr. Rescue (Lua, zlib, mature, inactive since 2016)
- Mr.Boom (C++, C, MIT, mature)
- Mrfuze (Python, LGPL-2.1, mature, inactive since 2008)
- Mtp Target (C++, GPL-2.0, mature, inactive since 2008)
- Murder In The Public Domain (C++, GPL-3.0, mature, inactive since 2013)
- MUSoSu (Java, GPL-3.0, beta, inactive since 2008)
- MxEngine (C++, 3-clause BSD, mature)
- n2048 (C, 2-clause BSD, beta, inactive since 2014)
- Naev (C, Lua, GPL-3.0, mature)
- Nanosaur Source Port (C, CC-BY-NC-SA-4.0, mature)
- NBlood (C, C++, Lua, GPL-2.0, mature)
- NEO-RAW (C++, GPL-2.0, mature, inactive since 2020)
- neoGFX (C++, GPL-3.0, beta)
- NeoLemmix (Pascal, ?, beta)
- Netacka (C, MIT, mature)
- NetHack (C, Custom, mature)
- NetMauMau (C++, LGPL-3.0, mature, inactive since 2015)
- NetPanzer (C++, GPL-2.0, beta)
- Netrek (C, Custom, mature, inactive since 2009)
- NetStatsBaseball (C, Public domain, mature)
- Neverball (C, C++, GPL-2.0, mature)
- Nexuiz (C++, GPL-2.0, mature)
- NFSIISE (C, MIT, mature)
- Nighthawk (C++, C, GPL-2.0, mature, inactive since 2004)
- Nikki and the Robots (Haskell, Lisp, LGPL-3.0, mature, inactive since 2012)
- Nikwi (C++, GPL-2.0, beta, inactive since 2012)
- Nitrosharp (C#, MIT, beta)
- NLarn (C, Lua, GPL-3.0, mature)
- No Gravity (C, GPL-2.0, mature, inactive since 2006)
- Nodes-of-Yesod (C#, MIT, beta, inactive since 2015)
- noiz2-droid (Java, 2-clause BSD, mature, inactive since 2015)
- Noiz2sa (C, C++, 2-clause BSD, beta, inactive since 2004)
- NorseWorld: Ragnarok (C#, GPL-3.0, beta)
- Not Pacman (Lua, WTFPL, mature, inactive since 2013)
- NOVA PINBALL (Lua, GPL-3.0, beta, inactive since 2017)
- Nox Imperii (C, GPL-3.0, mature, inactive since 2016)
- NStars! (C#, ?, beta, inactive since 2004)
- NullpoMino (Java, 3-clause BSD, mature)
- Numpty Physics (C++, GPL-3.0, beta, inactive since 2016)
- Nuncabola (Java, GPL-2.0, beta)
- Nuvie (C, C++, Lua, GPL-2.0, beta, inactive since 2018)
- NXEngine-evo (C++, C, GPL-3.0, mature)
- NXEngine (C, C++, GPL-3.0, mature)
- nXtank (Python, C++, GPL-3.0, beta, inactive since 2010)
- OceanPop (C++, MIT, mature)
- Odamex (C, C++, GPL-2.0, beta)
- Ogrian Carpet (C++, MIT, beta, inactive since 2018)
- OGS Mahjong (C++, GPL-3.0, mature, inactive since 2016)
- OldSkool Gravity Game (C++, C, GPL-3.0, mature, inactive since 2016)
- Omega (JavaScript, Ruby, AGPL-3.0, beta)
- Omnispeak (C, GPL-2.0, mature)
- One Hour One Life (C, C++, PHP, Public domain, mature)
- One is enough (Python, GPL-2.0, beta, inactive since 2008)
- One Way To Go (Lua, GPL-3.0, mature, inactive since 2011)
- Online Chess Club (PHP, JavaScript, GPL-2.0, mature)
- ONScripter (C++, GPL-2.0, mature, inactive since 2020)
- Oolite (Objective-C, C, JavaScript, GPL-2.0, mature)
- Open Apocalypse (C++, MIT, beta)
- Open Cube (C++, C, zlib, beta, inactive since 2017)
- Open Flood (Java, MIT, mature, inactive since 2018)
- Open Fodder (C, C++, GPL-3.0, mature)
- Open Fortress (C++, CC-BY-NC-SA-4.0, Custom, beta)
- Open Greedy (C, GPL-2.0, beta, inactive since 2017)
- Open Hexagon (C++, C, AFL-3.0, mature)
- Open Horizon (C++, MIT, beta)
- Open Imperium Galactica (Java, LGPL-3.0, mature)
- Open Jumpgate (C++, GPL-2.0, beta, inactive since 2017)
- Open Kick-Off (Java, MIT, beta)
- Open Legend RPG (None, Custom, mature)
- Open Meridian (C, C++, GPL-2.0, mature)
- Open Panzer (JavaScript, GPL-2.0, mature)
- Open Quartz (C, GPL-2.0, beta, inactive since 2004)
- Open Rails (C#, GPL-3.0, mature)
- Open Rodent's Revenge (C++, MIT, beta, inactive since 2018)
- Open RSC (Java, C++, C, Objective-C, AGPL-3.0, mature)
- Open Simulator (C#, 3-clause BSD, beta)
- Open Soccer Star (PHP, GPL-3.0, beta)
- Open Surge (C, GPL-3.0, beta)
- Open Syobon Action (C++, ?, beta, inactive since 2011)
- Open Tibia (C++, GPL-2.0, beta, inactive since 2014)
- Open Valley (C++, CC-BY-NC-SA-4.0, beta)
- Open Yahtzee (C++, GPL-2.0, mature, inactive since 2016)
- Open Zelda (C, C++, zlib, mature, inactive since 2015)
- Open76 (C#, GPL-3.0, beta, inactive since 2020)
- openage (C++, Python, GPL-3.0, beta)
- OpenAlchemist (C++, GPL-2.0, beta, inactive since 2010)
- OpenArena (Java, GPL-3.0, beta)
- OpenArena (C, GPL-2.0, mature, inactive since 2012)
- OpenAWE (C++, GPL-3.0, beta)
- OpenBiohazard2 (Go, MIT, beta)
- openblack (C, C++, GPL-3.0, beta)
- OpenBlok (C++, GPL-3.0, beta)
- OpenBlox (Python, Lua, GPL-3.0, beta, inactive since 2011)
- OpenBOR (C, C++, 3-clause BSD, mature)
- OpenBound (C#, GPL-3.0, mature)
- OpenBVE (C#, Public domain, mature)
- openc2e (C, C++, LGPL-2.1, beta)
- OpenCity (C++, GPL-2.0, beta, inactive since 2015)
- OpenClaw (C++, GPL-3.0, mature)
- OpenClonk (C, C++, ISC, mature)
- OpenCrystalCaves (C++, MIT, beta, inactive since 2017)
- OpenD2 (C, C++, GPL-3.0, beta)
- openDarkEngine (C++, GPL-2.0, beta, inactive since 2018)
- opendf (C++, GPL-3.0, beta)
- OpenDiablo2 (Go, GPL-3.0, mature)
- OpenDominion (PHP, AGPL-3.0, beta)
- openDOW (C, GPL-3.0, beta)
- OpenDR (C#, GPL-3.0, beta)
- OpenDrakan (C++, GPL-3.0, beta)
- OpenDUNE (C, GPL-2.0, mature)
- OpenDungeons (C++, GPL-3.0, beta)
- OpenE2140 (C++, GPL-3.0, beta, inactive since 2020)
- OpenEnroth (C++, LGPL-3.0, beta)
- OpenEtG (JavaScript, MIT, beta)
- OpenFire (C, MIT, beta, inactive since 2018)
- OpenFly (C, GPL-2.0, beta, inactive since 2001)
- OpenFNaF (C, MIT, beta)
- OpenGGS (C++, GPL-2.0, beta, inactive since 2017)
- OpenGL Test Drive Remake (C, C++, GPL-3.0, mature, inactive since 2015)
- Openglad (C++, GPL-2.0, mature, inactive since 2004)
- OpenGOAL (Lisp, C++, ISC, beta)
- OpenGoo (C, C++, GPL-3.0, beta, inactive since 2016)
- OpenGothic (C++, MIT, beta)
- OpenGTA (C++, Custom, beta, inactive since 2007)
- OpenHoMM (C++, GPL-3.0, beta, inactive since 2010)
- OpenHoW (C, C++, GPL-3.0, beta)
- OpenHV (C#, Lua, GPL-3.0, beta)
- OpenITG (C, C++, MIT, beta, inactive since 2017)
- OpenJazz (C++, GPL-2.0, beta)
- OpenJK (C, C++, GPL-2.0, beta)
- OpenJKDF2 (C, ISC, beta)
- OpenKeeper (Java, GPL-3.0, beta)
- OpenKrush (C#, GPL-3.0, beta)
- OpenLara (C++, C, 2-clause BSD, mature)
- OpenLiero (C++, C, Custom, mature, inactive since 2015)
- OpenLieroX (C++, LGPL-2.0, mature)
- OpenLoco (C++, MIT, mature)
- OpenMC2 (C++, GPL-3.0, beta, inactive since 2018)
- OpenMoHAA (C, C++, GPL-2.0, beta)
- OpenMoM (C, C++, GPL-3.0, beta)
- OpenMOO2 (Python, GPL-2.0, beta, inactive since 2011)
- OpenMortal (C++, Perl, GPL-2.0, beta, inactive since 2006)
- openMSX (C++, GPL-2.0, mature)
- OpenMW for Android (Kotlin, Java, GPL-3.0, mature)
- OpenMW (C++, GPL-3.0, mature)
- OpenNefia (C#, Lua, MIT, beta)
- OpenNFS (C, C++, MIT, beta)
- OpenNitemare3D (C#, GPL-3.0, beta, inactive since 2021)
- OpenNotrium (C++, GPL-3.0, beta)
- OpenNox (C, Go, GPL-3.0, mature)
- OpenOMF (C, C++, MIT, beta)
- OpenRA (C#, GPL-3.0, mature)
- OpenRaider (C, C++, GPL-2.0, beta, inactive since 2015)
- OpenRCT2 (C++, GPL-3.0, mature)
- OpenRoads (TypeScript, JavaScript, MIT, mature, inactive since 2014)
- OpenRTS (Python, GPL-2.0, beta, inactive since 2006)
- OpenRW (C, C++, GPL-3.0, beta)
- OpenSA (C#, Lua, GPL-3.0, mature)
- OpenSAGE (C#, LGPL-3.0, beta)
- OpenSC2K (JavaScript, GPL-3.0, beta)
- OpenSkyscraper (C++, GPL-2.0, beta)
- OpenSoccer (PHP, GPL-3.0, beta)
- OpenSolomonsKey (C++, Unlicense, beta)
- OpenSpades (C, C++, AngelScript, GPL-3.0, beta)
- OpenSR (C++, GPL-3.0, beta, inactive since 2017)
- OpenSupaplex (C, GPL-3.0, mature)
- OpenSWE1R (C, C++, GPL-2.0, beta)
- OpenTESArena (C++, MIT, beta)
- OpenTitus (C, GPL-3.0, beta, inactive since 2014)
- OpenTomb (C, C++, Lua, LGPL-3.0, beta)
- OpenTriad (Java, GPL-3.0, beta, inactive since 2017)
- OpenTS2 (C#, MPL-2.0, beta)
- OpenTTD (C++, GPL-2.0, mature)
- OpenTyrian2000 (C, GPL-2.0, mature)
- OpenTyrian (C, GPL-2.0, beta, inactive since 2018)
- OpenVice (C#, ?, beta, inactive since 2021)
- OpenVIII (C#, MIT, beta)
- OpenWar (Go, C, GPL-3.0, beta, inactive since 2018)
- OpenWebSoccer-Sim (PHP, LGPL-3.0, mature)
- OpenXcom (C++, GPL-3.0, mature)
- OpenXRay (C++, Lua, ?, mature)
- OpenYandere (C#, GPL-3.0, beta, inactive since 2018)
- Operation Citadel (C++, GPL-2.0, beta, inactive since 2000)
- OPMon (C++, GDScript, GPL-3.0, beta)
- Orbit-Hopper (C++, GPL-2.0, mature, inactive since 2019)
- Orbium (JavaScript, GPL-2.0, mature, inactive since 2018)
- Ordoor (Go, MIT, beta)
- OREGON 77 (Fortran, ISC, mature)
- Oreon Engine (Java, GPL-3.0, mature)
- ORIENT (C#, Java, GPL-2.0, mature, inactive since 2009)
- orona (CoffeeScript, GPL-2.0, beta, inactive since 2012)
- Ostrich Riders (C++, GPL-3.0, beta)
- osu! (C#, MIT, beta)
- Other-Life (C, C++, Custom, beta)
- Our Personal Space (Ren'Py, GPL-3.0, mature)
- Outer Space (Python, GPL-2.0, beta)
- Outpost HD (C++, 3-clause BSD, beta)
- ouzel (C, C++, Objective-C, 2-clause BSD, beta)
- Overgod (C, GPL-2.0, mature, inactive since 2005)
- Overgrowth (C, C++, Apache-2.0, mature)
- Oxygen Engine (C++, C, Apache-2.0, mature)
- Pac Go (Go, MIT, mature)
- Pacewar (Python, GPL-3.0, mature, inactive since 2017)
- Pachi (C, Python, GPL-2.0, mature)
- Pacman 吃豆游戏 (JavaScript, MIT, mature)
- pacman-canvas (JavaScript, CC-BY-SA-4.0, mature, inactive since 2018)
- Pacman (C++, Script, GPL-2.0, beta)
- PainTown (C++, Java, Python, 3-clause BSD, mature)
- Palapeli (C++, GPL-2.0, mature)
- Panel Attack (Lua, zlib, beta)
- Pang Zero (Perl, GPL-2.0, beta, inactive since 2007)
- Paper Isaac (ooc, MIT, beta, inactive since 2015)
- PaperCraft (Java, Apache-2.0, mature, inactive since 2018)
- PARPG (Python, GPL-3.0, beta, inactive since 2012)
- PARSEC47 (D, 2-clause BSD, beta, inactive since 2003)
- Pasang Emas (Vala, GPL-3.0, mature)
- Passage (C++, Public domain, mature, inactive since 2011)
- Pathogen Warrior (C++, C, GPL-2.0, beta, inactive since 2004)
- Pathological (Python, Script, GPL-2.0, beta, inactive since 2003)
- Pax Britannica (Lua, C, MIT, mature)
- PCExhumed (C++, Custom, beta)
- Penguin Command (C, GPL-2.0, mature, inactive since 2007)
- Pentagram (C++, GPL-2.0, beta, inactive since 2018)
- Pentobi (C++, GPL-3.0, mature)
- Peragro Tempus (C, C++, GPL-2.0, beta, inactive since 2012)
- Performous (C, C++, GPL-2.0, mature)
- Permafrost Engine (C, Python, GPL-3.0, mature)
- Phantasy Star Rebirth (C++, GPL-3.0, beta, inactive since 2013)
- phpRPG (PHP, GPL-2.0, beta, inactive since 2006)
- Physics Platformer (Java, MIT, beta, inactive since 2019)
- Physics Spacewar (Java, MIT, beta, inactive since 2019)
- PianOli (Java, GPL-3.0, mature)
- Pillows (Python, GPL-2.0, beta, inactive since 2007)
- Pingus (C++, Scheme, GPL-3.0, mature)
- Pink Pony (C++, GPL-3.0, mature, inactive since 2017)
- Pioneer (C, C++, Lua, Apache-2.0, GPL-3.0, mature)
- Pioneers (C, GPL-2.0, mature)
- PipePanic (Java, JavaScript, MIT, mature, inactive since 2016)
- PipeWalker (C++, GPL-3.0, beta, inactive since 2012)
- Pixel Dungeon (Java, GPL-3.0, mature, inactive since 2015)
- Pixel Wheels (Java, GPL-3.0, mature)
- PixelLight (C, C++, MIT, mature, inactive since 2012)
- Pizza Business (C++, GPL-2.0, mature, inactive since 2003)
- PlaneShift (C++, GPL-2.0, mature)
- Planet Conquest (Java, GPL-3.0, mature, inactive since 2017)
- Planet Lander (Python, MIT, mature, inactive since 2020)
- Planet Rider (GDScript, GPL-3.0, mature, inactive since 2015)
- Planetary Hoppers (Java, GPL-2.0, beta, inactive since 2003)
- Plasma (C++, Python, GPL-3.0, mature)
- Playir (C++, Apache-2.0, mature, inactive since 2014)
- Plee the Bear (Lisp, C++, Scheme, C, GPL-3.0, beta, inactive since 2017)
- Point & Hit (Java, GPL-3.0, mature, inactive since 2017)
- PokerTH (C++, AGPL-3.0, mature, inactive since 2017)
- Poland can into Space (Java, NPOSL-3.0, mature, inactive since 2018)
- Polis (Java, GPL-3.0, mature, inactive since 2016)
- POSTAL 1 Open Source (C++, GPL-2.0, beta, inactive since 2018)
- Potato Killer (Python, GPL-3.0, beta, inactive since 2011)
- Powermanga (C, GPL-3.0, beta, inactive since 2015)
- Powerslave EX (C, C++, GPL-3.0, beta, inactive since 2017)
- PowerslaveGDX (Java, Custom, beta)
- Powerslide remake (C++, MIT, beta)
- pq2 (C++, GPL-3.0, mature)
- PrBoom+ (C, GPL-2.0, mature, inactive since 2016)
- Prescription Wars (ColdFusion, JavaScript, GPL-3.0, mature, inactive since 2016)
- Pretend You're Xyzzy (Java, JavaScript, 2-clause BSD, mature, inactive since 2020)
- PrimeShooter (JavaScript, GPL-2.0, mature, inactive since 2010)
- Primrose (C++, Public domain, mature, inactive since 2009)
- Prince-Monogame (C#, GPL-2.0, beta)
- Privateer - Gemini Gold (C++, GPL-2.0, mature, inactive since 2012)
- progress-quest (C++, Python, MIT, mature)
- Project Alexandria (Python, ?, beta, inactive since 2007)
- Project Carrot (C++, MIT, beta, inactive since 2017)
- Project Dollhouse (C#, MPL-2.0, beta)
- Project Helena (Pascal, GPL-3.0, beta, inactive since 2018)
- Project Porcupine (C#, GPL-3.0, beta, inactive since 2019)
- Project-Uranium-Godot (GDScript, MIT, beta)
- Project: Starfighter (C, GPL-3.0, mature)
- ProQuake 4 (C, GPL-2.0, mature, inactive since 2018)
- proxx (TypeScript, JavaScript, Apache-2.0, mature)
- PSY PONG 3D (C, GPL-3.0, beta, inactive since 2009)
- PsyDoom (C, C++, GPL-3.0, mature)
- Pushover (C++, C, Lua, GPL-3.0, beta, inactive since 2018)
- Puzzle Moppet (C++, WTFPL, mature)
- PuzzleScript (JavaScript, MIT, mature)
- PyBreak360 (Python, GPL-3.0, mature, inactive since 2015)
- PyChess (Python, TypeScript, GPL-3.0, mature)
- pycraft (C, Python, GPL-2.0, mature, inactive since 2018)
- Pygame---Alien-Invasion (Python, GPL-3.0, beta, inactive since 2018)
- PyKaraoke (Python, C, LGPL-2.1, beta, inactive since 2011)
- Pyskool (Python, GPL-3.0, mature)
- PySol (Python, GPL-2.0, mature, inactive since 2004)
- Python Kye (Python, GPL-2.0, mature, inactive since 2010)
- Q-Gears (C, C++, GPL-2.0, beta, inactive since 2015)
- Q (Python, GPL-3.0, mature, inactive since 2013)
- Qonk (C++, GPL-2.0, beta, inactive since 2008)
- Quadrapassel (Vala, GPL-2.0, mature)
- Quake3e (C, GPL-2.0, beta)
- QuakeJS (JavaScript, MIT, mature)
- QuakeSpasm (C, GPL-2.0, mature)
- Quartz Engine (C++, 3-clause BSD, beta)
- Quatter (C++, GPL-2.0, mature, inactive since 2018)
- Quick Curver (C++, GPL-3.0, mature)
- R.E.L.I.V.E. (C++, MIT, beta)
- Rabbit Escape (Java, GPL-2.0, mature)
- Race Into Space (C, C++, GPL-2.0, mature)
- RacerJS (JavaScript, MIT, mature, inactive since 2010)
- RAD (Pascal, C, GPL-2.0, mature)
- Radakan (Python, Custom, beta, inactive since 2014)
- RadixEngine (C++, zlib, mature)
- Rails: an 18xx game system (Java, GPL-2.0, mature)
- Raincat (Haskell, 3-clause BSD, mature, inactive since 2018)
- ransack (Python, MIT, mature, inactive since 2016)
- Rapid Dominance (TypeScript, Apache-2.0, beta)
- Raptor: Call of the Shadows (C, GPL-3.0, beta)
- Raptor (C, C++, GPL-2.0, mature)
- RaumBaller (Java, GPL-3.0, mature)
- Raze (C++, GPL-2.0, mature)
- RBDOOM-3-BFG (C, C++, GPL-3.0, mature)
- re-private-eye (Python, 2-clause BSD, beta)
- Reconstruction of Super ZZT (Pascal, MIT, mature)
- Reconstruction of ZZT (Pascal, MIT, mature)
- Recursive Runner (C++, GPL-3.0, beta, inactive since 2017)
- Red Eclipse (C++, C, zlib, mature)
- Red Runner (C#, MIT, mature)
- RedneckGDX (Java, Custom, beta)
- Rednukem (C++, Custom, beta)
- REDriver2 (C++, C, MIT, beta)
- RedShift (C, C++, GPL-2.0, beta, inactive since 2008)
- ReflectionHLE (C, Lua, GPL-2.0, mature)
- REGoth (C++, GPL-3.0, MIT, mature)
- Reldens (JavaScript, MIT, mature)
- Reliquarium (Ada, GPL-2.0, mature)
- remc2 (C, GPL-3.0, mature)
- Remixed Dungeon (Java, GPL-3.0, mature)
- Remnants of the Precursors (Java, CC-BY-NC-ND-4.0, mature)
- reone (C++, GPL-3.0, beta)
- Replica Island (Java, Apache-2.0, mature, inactive since 2011)
- ReQbert (JavaScript, GPL-3.0, beta)
- Rescue! Max (Java, GPL-3.0, beta, inactive since 2013)
- ResidualVM (C++, GPL-2.0, beta)
- Retro Stack (Kotlin, GPL-3.0, mature)
- Return of Dr. Destructo (C++, MIT, mature, inactive since 2015)
- Return to the Roots (C++, GPL-3.0, mature)
- ReTux (Python, GPL-3.0, mature, inactive since 2018)
- rfk-inform (Script, Artistic License-2.0, mature)
- Ri-li (C++, GPL-3.0, mature, inactive since 2007)
- RickyD (C++, GPL-2.0, beta)
- Rigel Engine (C++, GPL-2.0, beta)
- Rigs of Rods (C, C++, AngelScript, GPL-3.0, mature)
- Riiablo (Java, Apache-2.0, beta)
- Rise of the Triad for Linux (C, GPL-2.0, mature, inactive since 2012)
- rlvm (C++, GPL-3.0, mature)
- Robbo (JavaScript, MPL-2.0, mature, inactive since 2016)
- Robot Redemption (C++, CC-BY-NC-SA-4.0, GPL-2.0, mature, inactive since 2014)
- rock-raiders-remake (JavaScript, MIT, beta)
- Rockbot (C++, GPL-2.0, mature)
- Rocks'n'Diamonds (C, GPL-2.0, mature)
- Rogue Clone IV (C, 3-clause BSD, mature, inactive since 2006)
- RogueBox Adventures (Python, GPL-3.0, mature)
- RogueSharp (C#, MIT, mature)
- Roguish (JavaScript, 3-clause BSD, beta, inactive since 2015)
- Room for Change (Java, Apache-2.0, mature, inactive since 2013)
- Rot Magus (JavaScript, Apache-2.0, CC0, beta)
- Roton (C#, ISC, beta, inactive since 2019)
- Rott94 (C, C++, GPL-2.0, beta)
- rottexpr (C, GPL-2.0, beta)
- RPG Tactical Fantasy Game (Python, GPL-3.0, mature)
- RPG-X (C, GPL-2.0, mature, inactive since 2015)
- rpgboss (Scala, JavaScript, AGPL-3.0, beta, inactive since 2017)
- rRootage (C, 2-clause BSD, beta, inactive since 2004)
- Ruby-warrior (Ruby, MIT, beta, inactive since 2012)
- RufasCube (Ada, GPL-2.0, mature)
- RufasSlider (C++, GPL-2.0, mature)
- RufasSwap (Ada, GPL-3.0, mature)
- RuneLite (Java, 2-clause BSD, mature)
- Runfield (JavaScript, GPL-3.0, mature, inactive since 2011)
- RuZZT (Rust, MIT, beta)
- Ryzom Core (C++, PHP, AGPL-3.0, mature)
- S.C.O.U.R.G.E. (C++, GPL-2.0, beta, inactive since 2008)
- SanAndreasUnity (C#, MIT, mature)
- sandspiel (Rust, JavaScript, TypeScript, MIT, beta)
- Sarah-Maries Eierjagd (C++, GPL-2.0, mature, inactive since 2005)
- sccopter (C, C++, MIT, beta, inactive since 2019)
- Scorched Moon (Python, GPL-3.0, beta)
- Scorched3D (C++, GPL-2.0, mature, inactive since 2014)
- Scrabble3D (Pascal, GPL-3.0, mature, inactive since 2015)
- Scrap (C, C++, GPL-2.0, mature, inactive since 2017)
- SCSharp (C#, MIT, beta, inactive since 2011)
- SDL Asylum (C, GPL-3.0, mature, inactive since 2009)
- SDL Bomber (C, GPL-2.0, mature, inactive since 2012)
- SDL Sopwith (C, C++, GPL-2.0, mature, inactive since 2014)
- SDL-Ball (C++, GPL-3.0, mature, inactive since 2016)
- SDLPoP (C, GPL-3.0, mature)
- Sea-Wolf (JavaScript, MIT, mature)
- Seafood Berserker! (Java, GPL-3.0, mature, inactive since 2018)
- Search for the Red Herring (Python, GPL-2.0, mature, inactive since 2006)
- Secret Maryo Chronicles (C++, GPL-3.0, mature, inactive since 2009)
- Sengoku: Warring States of Japan (C++, Lua, MIT, beta, inactive since 2008)
- sensitive-js (JavaScript, Custom, beta, inactive since 2017)
- Sentient Storage (Python, Public domain, mature)
- Serious Engine (C, C++, GPL-2.0, mature, inactive since 2017)
- Serious Sam Android (C, C++, GPL-2.0, mature, inactive since 2020)
- Serious Sam Classic (C++, GPL-2.0, mature)
- Settlers III remake (Java, MIT, beta)
- Seven Kingdoms: Ancient Adversaries (C++, GPL-2.0, mature)
- sfall (C++, C, GPL-3.0, mature)
- sh3redux (C, C++, GPL-3.0, beta, inactive since 2019)
- shadow-of-the-beast-html5 (JavaScript, Apache-2.0, beta, inactive since 2017)
- Shadowgrounds (C++, Custom, beta, inactive since 2017)
- SharpKonquest (C#, GPL-2.0, mature, inactive since 2007)
- Shattered Pixel Dungeon (Java, GPL-3.0, mature)
- Ship of Harkinian (C, C++, MIT, mature)
- shiromino (C++, MIT, beta)
- Shockolate (C, GPL-3.0, beta)
- Shotgun Debugger (C++, GPL-2.0, mature, inactive since 2005)
- Siege of Avalon : Open Source (Pascal, Custom, beta, inactive since 2011)
- Signus: The Artefact Wars (C++, GPL-2.0, mature)
- SilverTree (C++, GPL-3.0, beta, inactive since 2007)
- Simitone (C#, MPL-2.0, beta)
- Simon Tatham's Portable Puzzle Collection (C, MIT, mature)
- Simple Brick Games (Java, GPL-3.0, mature, inactive since 2017)
- Simple Platformer (Java, MIT, beta, inactive since 2019)
- Simple Sokoban (C, Objective-C, GPL-3.0, mature, inactive since 2014)
- Simple-Solitaire (Java, GPL-3.0, mature)
- Simsu (C++, GPL-3.0, mature)
- Simutrans (C++, Artistic License-1.0, mature)
- Sinatra (C, GPL-3.0, mature, inactive since 2008)
- Sine (C, C++, MIT, beta)
- Sintel The Game (Python, MIT, beta, inactive since 2014)
- Skifree-HTML5-clone (JavaScript, GPL-3.0, beta, inactive since 2011)
- skifree.js (JavaScript, MIT, mature, inactive since 2016)
- Skrupel - Tribute Compilation (PHP, JavaScript, GPL-2.0, mature, inactive since 2011)
- SLASH'EM (C, C++, Custom, beta, inactive since 2007)
- Slay (Java, GPL-3.0, beta, inactive since 2010)
- Sleep Is Death (C++, ?, mature, inactive since 2018)
- SliJewel (Pascal, GPL-3.0, mature, inactive since 2020)
- SliLights (Pascal, GPL-3.0, mature, inactive since 2021)
- SliLumns (Pascal, GPL-3.0, mature, inactive since 2020)
- Slime Volley (C, GPL-3.0, mature, inactive since 2010)
- Slime Volleyball (C++, 3-clause BSD, beta)
- SliMind (Pascal, GPL-3.0, mature, inactive since 2020)
- SliMine (Pascal, GPL-3.0, mature, inactive since 2020)
- Slingshot (Python, GPL-2.0, beta, inactive since 2007)
- SliPeg (Pascal, GPL-3.0, mature, inactive since 2020)
- SliSame (Pascal, GPL-3.0, mature, inactive since 2020)
- SliSnake (Pascal, GPL-3.0, mature, inactive since 2020)
- SliTris (Pascal, GPL-3.0, mature, inactive since 2020)
- Slot-Racers (C, C++, GPL-3.0, mature, inactive since 2008)
- Sludge (C, C++, Objective-C, LGPL-2.1, mature)
- Slune (Python, GPL-2.0, mature, inactive since 2007)
- Smash Battle (C++, GPL-2.0, beta, inactive since 2011)
- Smash (JavaScript, MIT, mature)
- Smolpxl (JavaScript, AGPL-3.0, mature)
- snake (Java, WTFPL, mature, inactive since 2017)
- Snelps (Ruby, LGPL-2.1, beta, inactive since 2012)
- Snowballz (Python, GPL-2.0, beta, inactive since 2007)
- Sokoban (CoffeeScript, AGPL-3.0, mature)
- SokoSolve (C#, GPL-3.0, mature, inactive since 2009)
- SolarWolf (Python, LGPL-2.1, mature, inactive since 2004)
- Soldank (Rust, MIT, beta)
- Soldat (C, Pascal, MIT, mature)
- Sole Collector (Java, MIT, beta, inactive since 2018)
- Song of Albion (C, C++, Apache-2.0, mature, inactive since 2011)
- Sonic Robo Blast 2 (C, C++, GPL-2.0, mature)
- Sootl (Elm, JavaScript, GPL-2.0, beta, inactive since 2016)
- Sopwith 3 (C, C++, Objective-C, GPL-2.0, beta, inactive since 2003)
- Source of Tales (Lua, GPL-3.0, mature, inactive since 2013)
- Sourcehold (C++, MIT, beta)
- Space Faring (Java, GPL-3.0, beta)
- Space Harrier Clone (C, C++, MIT, beta, inactive since 2018)
- Space Nerds In Space (C, Lua, GPL-2.0, beta)
- Space Opera (Java, GPL-2.0, beta, inactive since 2008)
- Space Station 13 (DM, AGPL-3.0, mature)
- Space Trader for Android (Java, GPL-3.0, mature, inactive since 2016)
- Space Trader for Windows (C#, GPL-2.0, mature, inactive since 2009)
- Space War (Java, Apache-2.0, mature)
- SpaceCadetPinball (C++, MIT, mature)
- SpacePeng! (Java, GPL-3.0, mature, inactive since 2017)
- SpaceTrader for Java (Java, GPL-2.0, mature, inactive since 2010)
- SpaceZero (C, GPL-3.0, beta)
- Spartan Engine (C, C++, MIT, beta)
- Speed Dreams (C++, GPL-2.0, mature)
- Spelling Bee (JavaScript, TypeScript, MIT, mature)
- Spice Trade (Java, LGPL-2.1, mature, inactive since 2005)
- splexhd (C++, GPL-2.0, beta, inactive since 2012)
- Spludlow Tetris (C#, GPL-3.0, mature, inactive since 2018)
- Spooker Framework (C#, MIT, beta, inactive since 2014)
- Spring: 1944 (Lua, GPL-2.0, CC-BY-NC-3.0, mature)
- Spring (C++, C, Lua, GPL-2.0, mature)
- SRB2Kart (C, C++, GPL-2.0, mature)
- SS13 Remake (C#, GPL-3.0, beta, inactive since 2015)
- Star Maiden Astraea Rio (Ren'Py, MIT, mature)
- Star Ruler 2 (C, C++, MIT, mature)
- star-control2 (C, C++, MIT, mature)
- Star-Wars-III (Python, GPL-2.0, mature, inactive since 2014)
- StarBlastrix (C++, GPL-2.0, beta, inactive since 2006)
- Stareater (C#, GPL-3.0, beta)
- Stargus (C++, Lua, GPL-2.0, beta, inactive since 2010)
- StarMines: The Next Generation (Scala, GPL-3.0, mature)
- Stars! Nova (C#, GPL-2.0, beta)
- starshatter-open (C++, 3-clause BSD, beta, inactive since 2015)
- Starun (Java, GPL-3.0, mature, inactive since 2017)
- Steamer Duck (Python, CC0, beta)
- Stendhal (Java, GPL-2.0, mature)
- StepMania (C, C++, Lua, MIT, mature)
- SteveTech1 (Java, MIT, beta, inactive since 2019)
- Stockfish (C++, GPL-3.0, mature)
- Stone Kingdoms (Lua, Apache-2.0, beta)
- Story of a Lost Sky (Python, 3-clause BSD, mature)
- Stratagus (C++, GPL-2.0, mature)
- StressFreeZone (C++, Lua, GPL-3.0, beta, inactive since 2007)
- Strife: Veteran Edition (C, C++, Objective-C, GPL-3.0, beta, inactive since 2016)
- Stringrolled (Python, Public domain, beta, inactive since 2008)
- Stunt Rally (C, C++, GPL-3.0, mature)
- Sudokuki (C, Java, GPL-3.0, mature, inactive since 2016)
- Summoning Wars (C, C++, Lua, GPL-3.0, beta, inactive since 2014)
- SunDog Resurrection (Java, Python, Artistic License-1.0, beta)
- Sundog: Frozen Legacy (C, Python, MIT, mature)
- sundog (C, C++, Python, MIT, beta)
- Supaxl (JavaScript, MIT, mature)
- Super Bombinhas (Ruby, GPL-3.0, mature)
- Super Mario Bros. X (Visual Basic, MIT, mature, inactive since 2020)
- Super Methane Brothers for Wii and GameCube (C++, GPL-2.0, beta, inactive since 2018)
- Super Methane Brothers (C++, GPL-2.0, mature, inactive since 2011)
- Super Retro Mega Wars (Kotlin, GPL-3.0, beta)
- Super Tilt Bro (Assembly, Python, WTFPL, mature)
- Super Transball 2 (C++, GPL-2.0, mature, inactive since 2005)
- Supercars III (Java, ?, mature, inactive since 2014)
- SuperFoulEgg (Objective-C, C, MIT, mature, inactive since 2014)
- SuperTux (C++, GPL-3.0, beta)
- SuperTuxKart (C++, C, GPL-3.0, mature)
- SuperTuxParty (GDScript, GPL-3.0, beta)
- Supremacy (C#, MS-RL, beta, inactive since 2014)
- Survivor (JavaScript, CC-BY-NC-3.0, mature)
- Swappy Jigsaw (Pascal, GPL-3.0, mature, inactive since 2019)
- SWP (C, C++, GPL-2.0, mature)
- Syndicate Wars Port (C, GPL-3.0, beta, inactive since 2010)
- System Syzygy (Rust, GPL-3.0, mature, inactive since 2018)
- T-Bots (C, C++, GPL-2.0, beta, inactive since 2004)
- T^3 (C++, GPL-2.0, beta, inactive since 2005)
- Tabletop Club (GDScript, MIT, beta)
- Tactics Squad (C++, GPL-2.0, beta, inactive since 2007)
- Taggem (JavaScript, AGPL-3.0, beta, inactive since 2014)
- Taisei Project (C, Python, MIT, mature)
- Tales of Maj'Eyal (C, Lua, GPL-3.0, mature)
- Tanglet (C++, GPL-3.0, mature)
- Tangomon (Python, GPL-3.0, mature, inactive since 2017)
- Tank: Zone of Death (C++, Lua, GPL-3.0, beta, inactive since 2017)
- TankistOnline (Python, GPL-3.0, beta)
- Tanks of Freedom (GDScript, MIT, mature)
- Tapir (C, Ruby, Apache-2.0, MIT, beta, inactive since 2017)
- Taponium (Java, GPL-3.0, mature, inactive since 2019)
- Team Tactics (Java, MIT, beta, inactive since 2016)
- TecnoballZ (C++, GPL-3.0, beta, inactive since 2016)
- Teeworlds (C, C++, zlib, beta)
- TekwarGDX (Java, Custom, beta)
- Tenes Empanadas Graciela (C, JavaScript, Perl, C++, GPL-2.0, beta, inactive since 2015)
- Tennix! (C, C++, GPL-2.0, mature)
- TermFrogger (Ada, GPL-3.0, mature)
- TerminalApps (Ada, GPL-3.0, mature)
- terrarium (C++, Script, GPL-2.0, beta)
- TES3MP (C++, GPL-3.0, beta)
- TetraVex (Swift, GPL-3.0, beta)
- Tetrepetete (C++, GPL-2.0, mature)
- Tetris (in C and NCURSES) (C, 3-clause BSD, mature)
- Tetzle (C++, GPL-3.0, mature)
- The Battle for Wesnoth (C, C++, Java, Python, Lua, GPL-2.0, mature)
- The Bub's Brothers (Python, C, MIT, mature, inactive since 2013)
- The Butterfly Effect (C++, GPL-2.0, beta)
- The Castles of Dr. Creep (C++, Script, GPL-3.0, mature)
- The Catacomb (C, C++, GPL-2.0, mature, inactive since 1990)
- The Clans (C, Objective-C, GPL-2.0, beta, inactive since 2003)
- The Dark Mod (C++, GPL-3.0, mature)
- The Endless Dungeons (C, CC-BY-NC-SA-2.0, mature, inactive since 2015)
- The Epic of Heroes (C++, GPL-3.0, beta, inactive since 2015)
- The Eternity Engine (C, C++, GPL-3.0, mature)
- The Force Engine (C++, GPL-2.0, beta)
- The House (JavaScript, MIT, mature, inactive since 2019)
- The hunt for the lost rainbow jewels (Jewelhunt) (Java, GPL-2.0, beta)
- The Knights of Alentejo (Java, C++, 2-clause BSD, beta)
- The Legend of Edgar (C, GPL-2.0, mature)
- The Mana World (C++, Script, GPL-2.0, mature)
- The Powder Toy (C++, C, Lua, Python, GPL-3.0, mature)
- The Rush (C++, GPL-2.0, beta, inactive since 2011)
- The Secret Chronicles of Dr. M. (C++, GPL-3.0, mature)
- The Ur-Quan Masters (C, GPL-2.0, mature, inactive since 2011)
- The-Trail (Java, MIT, Apache-2.0, beta, inactive since 2018)
- Theme Park Builder 3D CAD (C++, GPL-3.0, beta, inactive since 2013)
- TheXTech (C++, GPL-3.0, mature)
- thiefcatcher (C++, GPL-3.0, beta)
- Threes-C (C, Objective-C, MIT, mature, inactive since 2015)
- Threes.el (Emacs Lisp, GPL-3.0, mature)
- Thrive (C++, AngelScript, JavaScript, C#, GPL-3.0, beta)
- Thrust (C, GPL-2.0, beta, inactive since 2006)
- Thugaim (Java, MIT, mature, inactive since 2017)
- Thunder Engine (C++, Apache-2.0, beta)
- Thunder&Lightning (C, C++, Io, GPL-2.0, beta, inactive since 2015)
- Thyme (C, C++, GPL-2.0, beta)
- TIC-80 (C, Java, C++, Lua, MIT, beta)
- Tile World (C, GPL-2.0, mature, inactive since 2015)
- TinTin++ (C, GPL-3.0, mature)
- Tiny Tris (C, GPL-3.0, mature)
- Tiny Wings (Objective-C, C, C++, MIT, beta)
- Titan Tactics (GDScript, CC0, beta)
- TOMB5 (C, C++, MIT, beta)
- Toppler (C++, GPL-2.0, mature, inactive since 2012)
- TORCS, The Open Racing Car Simulator (C++, C, PHP, GPL-2.0, mature, inactive since 2016)
- Tornado (C, GPL-2.0, mature, inactive since 2009)
- Torque 2D (C++, C, MIT, mature)
- Torque 3D (C++, C, MIT, mature)
- Torrega Race (Lua, GPL-3.0, mature, inactive since 2015)
- Torso Ninja 2 (Python, GPL-3.0, mature, inactive since 2017)
- Torso Ninja (Python, GPL-3.0, mature, inactive since 2017)
- TOSIOS (TypeScript, MIT, beta)
- Total Annihilation 3D (C++, C, Lua, GPL-2.0, beta, inactive since 2017)
- Tower Building Game (JavaScript, MIT, mature)
- Tower Defense (JavaScript, MIT, beta, inactive since 2014)
- Tower Toppler (C++, GPL-2.0, mature, inactive since 2012)
- TowerJumper (C++, GDScript, GPL-3.0, mature)
- Trackballs (C++, Scheme, GPL-2.0, mature)
- Train (Java, 3-clause BSD, beta)
- Transcend (C++, ?, beta, inactive since 2005)
- Transfusion (C, GPL-2.0, beta, inactive since 2007)
- Tremfusion (C, GPL-2.0, mature, inactive since 2009)
- Tremulous (C, GPL-2.0, mature, inactive since 2016)
- Tressette (C++, GPL-2.0, mature, inactive since 2017)
- Trigger Rally (JavaScript, GPL-3.0, beta)
- Trinity Reign (C++, C, GPL-3.0, beta, inactive since 2013)
- Trip on the Funny Boat (Python, GPL-2.0, mature, inactive since 2020)
- TripleA (Java, GPL-2.0, mature)
- TROPHY (C++, GPL-2.0, mature, inactive since 2012)
- TrueCraft (C#, MIT, beta, inactive since 2018)
- Tttris (Java, GPL-3.0, mature, inactive since 2012)
- Tumbly Towers (Java, MIT, beta, inactive since 2017)
- Tumiki Fighters (D, C++, 2-clause BSD, mature, inactive since 2005)
- Turious (C, GPL-3.0, beta, inactive since 2014)
- Turn of War (Java, GPL-3.0, beta, inactive since 2014)
- Turo (PHP, GDScript, GPL-3.0, mature, inactive since 2018)
- TurokEX (C++, C, GPL-2.0, beta, inactive since 2014)
- TUSSLE (Python, GPL-3.0, mature, inactive since 2017)
- Tux Builder (GDScript, GPL-3.0, beta)
- Tux Football (C++, GPL-2.0, beta, inactive since 2012)
- Tux Memory (Java, GPL-3.0, mature, inactive since 2014)
- Tux of Math Command (C, GPL-3.0, mature, inactive since 2011)
- Tux Paint (C, C++, GPL-2.0, beta)
- Tux Racer (C, C++, GPL-2.0, beta, inactive since 2001)
- Tux Rider (C, GPL-2.0, mature, inactive since 2019)
- Tuxemon (Python, GPL-3.0, beta)
- TuxKart (C++, GPL-2.0, beta, inactive since 2004)
- TVTower (BlitzMax, Lua, Custom, mature)
- twin-e (C, GPL-2.0, beta, inactive since 2015)
- TwinEngine (C, GPL-2.0, mature, inactive since 2015)
- Tyger (Python, ?, beta, inactive since 2016)
- Tyrian Remake (Java, GPL-2.0, beta)
- TyrQuake (C, GPL-2.0, beta)
- UA_source (C++, GPL-2.0, beta)
- UAlbion (C#, MIT, beta)
- UchuServer (C#, AGPL-3.0, mature)
- Uebergame (TorqueScript, C#, MIT, mature)
- UFO2000 (C, C++, Lua, GPL-2.0, mature, inactive since 2012)
- UFO: Alien Invasion (C, C++, GPL-2.0, mature)
- Ularn (C, C++, GPL-2.0, mature, inactive since 2018)
- UlDunAd (Python, GPL-3.0, beta, inactive since 2011)
- Ultima 5 Redux (C#, MIT, beta)
- Ultimate Stunts (C++, GPL-2.0, beta, inactive since 2013)
- UltraStar Deluxe (Pascal, GPL-2.0, mature)
- UltraStar Play (C#, MIT, beta)
- uMario (C++, GPL-2.0, beta, inactive since 2016)
- Umbra (Python, Custom, beta, inactive since 2002)
- Umoria (C, C++, GPL-3.0, mature)
- Unciv (Kotlin, MPL-2.0, mature)
- Underworld Adventures (C++, Lua, GPL-2.0, beta)
- UnderworldExporter (C#, C++, MIT, mature)
- uninvited (C, C++, Artistic License-2.0, beta, inactive since 2016)
- UnityPacmania (C#, Custom, mature)
- unitystation (C#, AGPL-3.0, beta)
- Unknown Horizons Godot Engine Port (GDScript, GPL-2.0, beta)
- Unknown Horizons (Python, GPL-2.0, beta)
- UnNetHack (C, Custom, mature)
- Unvanquished (C, C++, GPL-3.0, mature)
- UTEngine (C++, zlib, beta)
- Valyria Tear (Lua, C++, C, GPL-2.0, mature)
- Vamos (C++, Python, GPL-3.0, beta, inactive since 2014)
- Vangers (C++, GPL-3.0, mature)
- Vanilla-Conquer (C, C++, Assembly, GPL-3.0, mature)
- Vault13 (Rust, GPL-3.0, beta, inactive since 2020)
- VCMI (C++, GPL-2.0, mature)
- VDrift (C++, GPL-3.0, mature, inactive since 2014)
- Vector Pinball (Java, GPL-3.0, mature)
- Vectoroids (C, GPL-2.0, mature, inactive since 2002)
- Vegan on a Desert Island (Lua, GPL-3.0, beta)
- Veloren (Rust, GPL-3.0, beta)
- Venzone (Haskell, GPL-3.0, mature)
- Veraball (GDScript, MIT, beta, inactive since 2016)
- Vertigo (C, GPL-2.0, beta, inactive since 2002)
- Violetland (C++, GPL-3.0, beta)
- Vircadia (C++, Apache-2.0, mature)
- Virus Attack (Java, AGPL-3.0, mature)
- Visual Pinball (C++, MAME, mature)
- vitetris (C, 2-clause BSD, beta)
- vkQuake (C, C++, GPL-2.0, mature)
- VMS Empire (C, GPL-2.0, mature, inactive since 2014)
- Vocaluxe (C#, C++, GPL-3.0, beta)
- Vorton (C, GPL-3.0, beta, inactive since 2004)
- Voxelands (C++, C, GPL-3.0, beta)
- Vulture's Eye (C++, C, NetHack General Public License, mature, inactive since 2015)
- VVVVVV (ActionScript, C++, Custom, mature)
- Wagic, the Homebrew (C++, C, Objective-C, 3-clause BSD, beta)
- Walic (Kotlin, Apache-2.0, mature)
- WallBall (Haxe, JavaScript, GPL-3.0, mature)
- War Of Kingdom (C, C++, GPL-2.0, beta)
- War1 (C, zlib, beta)
- Warcraft Remake (Java, GPL-3.0, beta)
- warcraft-remake (Java, GPL-2.0, beta)
- Wargamer (C++, GPL-2.0, mature, inactive since 2003)
- Wargus (C++, Lua, C, GPL-2.0, mature)
- Wario-Land-3 (Python, MIT, beta, inactive since 2018)
- WarMUX (C++, GPL-2.0, beta, inactive since 2018)
- Warp Rogue (C, GPL-3.0, beta, inactive since 2010)
- WarriorJS (JavaScript, MIT, mature, inactive since 2018)
- Warzone 2100 (C++, GPL-2.0, mature)
- Waste's Edge (Python, GPL-2.0, beta)
- Waterkube (Go, MIT, mature)
- WAtomic (Pascal, GPL-2.0, mature, inactive since 2005)
- WebChess (PHP, GPL-3.0, mature, inactive since 2010)
- WebFun (TypeScript, MIT, beta)
- WebHangman (JavaScript, GPL-2.0, mature, inactive since 2003)
- WebQuake (JavaScript, GPL-2.0, mature, inactive since 2019)
- Which Way Is Up? (Python, GPL-2.0, beta, inactive since 2008)
- Widelands (C, C++, Lua, Python, GPL-2.0, mature)
- Windstille (C++, Scheme, GPL-3.0, beta, inactive since 2017)
- Wintermute Engine (C++, C, MIT, beta, inactive since 2013)
- WinWar (C#, MIT, mature)
- Witch Blast (C++, GPL-3.0, beta, inactive since 2015)
- WitchavenGDX (Java, Custom, beta)
- Wizardry Legacy (C++, C, Objective-C, GPL-3.0, beta, inactive since 2018)
- Wizards Magic (Python, GPL-2.0, mature, inactive since 2012)
- Wizznic! (C, GPL-3.0, beta, inactive since 2016)
- wkbre2 (C++, GPL-3.0, beta)
- wkbre (C++, C, GPL-3.0, beta)
- Wograld (C, GPL-2.0, beta)
- Wolf3dX (C#, GPL-2.0, beta)
- Wolf4SDL (C, GPL-2.0, mature)
- Wolfpack Empire (C, GPL-3.0, mature)
- Word War vi (C, GPL-2.0, mature)
- World of Heroes (Python, 3-clause BSD, beta, inactive since 2009)
- World of Might and Magic (C++, LGPL-3.0, beta)
- World of Phaos (PHP, GPL-2.0, mature, inactive since 2011)
- WTF?! Adventure (JavaScript, WTFPL, mature)
- WWW (JavaScript, GPL-3.0, beta, inactive since 2014)
- wxLaserTank (C++, GPL-2.0, mature, inactive since 2009)
- Wyrmsun (Lua, C++, GPL-2.0, mature)
- X-Force: Fight For Destiny (Pascal, GPL-2.0, beta, inactive since 2011)
- X-Moto (C++, GPL-2.0, mature, inactive since 2014)
- XArchon (C, C++, GPL-2.0, beta, inactive since 2003)
- Xargon (C++, GPL-3.0, mature, inactive since 2015)
- xBaK (C++, GPL-3.0, beta, inactive since 2013)
- XBill (C, Script, GPL-2.0, mature, inactive since 2001)
- XBlast (C, Java, GPL-2.0, mature, inactive since 2005)
- Xconq (C++, C, Script, GPL-2.0, mature, inactive since 2005)
- xdigger (C, GPL-2.0, mature, inactive since 1999)
- xDuke (C, GPL-2.0, beta, inactive since 2010)
- Xenowar (C, C++, GPL-3.0, mature, inactive since 2014)
- XEvil (C++, GPL-2.0, mature)
- xGreed (Pascal, Custom, beta)
- XInvaders 3D (C, Objective-C, GPL-2.0, mature, inactive since 2000)
- Xjig (C, Custom, mature)
- XL Engine (C++, MIT, beta, inactive since 2018)
- XMage (Java, MIT, mature)
- Xonotic (C, C++, GPL-3.0, mature)
- XorCurses (C, GPL-3.0, beta, inactive since 2012)
- XPilot NG (C, GPL-2.0, mature, inactive since 2010)
- XPilot (C, C++, GPL-2.0, mature, inactive since 2010)
- XScavenger (C, GPL-2.0, mature, inactive since 2015)
- XSera (C, Lua, MIT, beta, inactive since 2010)
- XSkat (Java, Custom, mature)
- xsoldier (C, GPL-2.0, mature, inactive since 2011)
- XSwing Plus (Java, GPL-3.0, beta, inactive since 2010)
- xu4 (C++, GPL-2.0, mature, inactive since 2016)
- Xultris (JavaScript, XUL, MPL-1.1, mature, inactive since 2011)
- Xye (C++, zlib, beta, inactive since 2013)
- xygineXT (C++, zlib, beta)
- Yamagi Quake II (C, GPL-2.0, mature)
- Yet Another Doom Clone (JavaScript, Python, GPL-3.0, mature)
- Yet Another Engine (MoonScript, Java, Lua, MIT, beta, inactive since 2016)
- YKnytt (C#, MIT, beta)
- Yo Frankie! (Blender Script, ?, mature, inactive since 2009)
- Yorg (Python, GPL-3.0, beta)
- YSoccer (Java, GPL-2.0, mature)
- Zandronum (C, Custom, mature, inactive since 2017)
- ZAngband (C, Custom, mature, inactive since 2005)
- Zatacka X (C, GPL-3.0, beta)
- Zatacka (C, C++, GPL-2.0, beta, inactive since 2007)
- Zauberer (None, ISC, beta, inactive since 2018)
- Zaz (C++, GPL-3.0, beta, inactive since 2010)
- ZDoom (C, C++, ZenScript, GPL-3.0, mature)
- Zed Online (C++, ?, mature)
- Zelda Classic (C, C++, GPL-3.0, mature)
- zelda3 (C, MIT, mature)
- Zelda: Mystery of Solarus DX (Lua, GPL-3.0, mature)
- Zen! (Java, GPL-2.0, mature)
- ZEQ2 Lite (Script, ?, beta)
- Zero Ballistics (C++, MIT, mature, inactive since 2013)
- Zero-K (Lua, GPL-2.0, mature)
- Zetawar (Clojure, MIT, mature)
- ZGB (C, Assembly, C++, MIT, mature)
- Zod Engine (C++, ?, mature, inactive since 2018)
- Zone of Control (Rust, Apache-2.0, beta, inactive since 2017)
- zorkClone (Java, Apache-2.0, beta)
- Zugspiel (C++, GPL-2.0, beta, inactive since 2004)
- zztgo (Go, MIT, beta)