diff --git a/Makefile b/Makefile
index dc8ca36d..c389c6e7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,5 @@
 TOPDIR = $(realpath .)
 
-SUBDIRS = tools lib effects
 SUBDIRS = tools lib system effects
 EXTRA-FILES = tags cscope.out
 CLEAN-FILES = bootloader.bin a500rom.bin addchip.bootblock.bin vbrmove
diff --git a/effects/anim-polygons/Makefile b/effects/anim-polygons/Makefile
index 4043fd66..ebc94a50 100644
--- a/effects/anim-polygons/Makefile
+++ b/effects/anim-polygons/Makefile
@@ -6,6 +6,6 @@ PNG2C.dancing-pal := --pixmap gradient,16x22x12
 
 include $(TOPDIR)/build/effect.mk
 
-%.c: %.svg
+data/%.c: data/%.svg
 	@echo "[ANIM] $(DIR)$< -> $(DIR)$@"
 	$(PYTHON3) encode.py $< > $@
diff --git a/effects/anim-polygons/anim-polygons.c b/effects/anim-polygons/anim-polygons.c
index af2595ea..9670154d 100644
--- a/effects/anim-polygons/anim-polygons.c
+++ b/effects/anim-polygons/anim-polygons.c
@@ -136,4 +136,4 @@ static void Render(void) {
   maybeSkipFrame = 1;
 }
 
-EFFECT(AnimPolygons, NULL, NULL, Init, Kill, Render);
+EFFECT(AnimPolygons, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/anim/anim.c b/effects/anim/anim.c
index 1f722699..6481d627 100644
--- a/effects/anim/anim.c
+++ b/effects/anim/anim.c
@@ -109,4 +109,4 @@ static void Render(void) {
   active = (active + 1) % (DEPTH + 1);
 }
 
-EFFECT(Anim, Load, UnLoad, Init, Kill, Render);
+EFFECT(Anim, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/ball/ball.c b/effects/ball/ball.c
index 3aad7820..59cd9a5b 100644
--- a/effects/ball/ball.c
+++ b/effects/ball/ball.c
@@ -347,4 +347,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Ball, NULL, NULL, Init, Kill, Render);
+EFFECT(Ball, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/blurred/blurred.c b/effects/blurred/blurred.c
index 948f2cf6..0fb6b63d 100644
--- a/effects/blurred/blurred.c
+++ b/effects/blurred/blurred.c
@@ -140,4 +140,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Blurred, Load, UnLoad, Init, Kill, Render);
+EFFECT(Blurred, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/blurred3d/blurred3d.c b/effects/blurred3d/blurred3d.c
index 29911fdb..d53e5d06 100644
--- a/effects/blurred3d/blurred3d.c
+++ b/effects/blurred3d/blurred3d.c
@@ -495,4 +495,4 @@ static void Render(void) {
   swapr(screen0, screen1);
 }
 
-EFFECT(Blurred3D, Load, UnLoad, Init, Kill, Render);
+EFFECT(Blurred3D, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/bobs3d/bobs3d.c b/effects/bobs3d/bobs3d.c
index 074a883c..a995e29f 100644
--- a/effects/bobs3d/bobs3d.c
+++ b/effects/bobs3d/bobs3d.c
@@ -253,4 +253,4 @@ static void Render(void) {
   swapr(screen0, screen1);
 }
 
-EFFECT(Bobs3D, NULL, NULL, Init, Kill, Render);
+EFFECT(Bobs3D, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/bumpmap-rgb/bumpmap-rgb.c b/effects/bumpmap-rgb/bumpmap-rgb.c
index 855886f3..25da6f80 100644
--- a/effects/bumpmap-rgb/bumpmap-rgb.c
+++ b/effects/bumpmap-rgb/bumpmap-rgb.c
@@ -381,4 +381,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(BumpMapRGB, Load, UnLoad, Init, Kill, Render);
+EFFECT(BumpMapRGB, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/butterfly-gears/butterfly-gears.c b/effects/butterfly-gears/butterfly-gears.c
index 4023bb11..6dbfb25b 100644
--- a/effects/butterfly-gears/butterfly-gears.c
+++ b/effects/butterfly-gears/butterfly-gears.c
@@ -203,4 +203,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(ButterflyGears, NULL, NULL, Init, Kill, Render);
+EFFECT(ButterflyGears, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/circles/circles.c b/effects/circles/circles.c
index 404ee346..a66447c9 100644
--- a/effects/circles/circles.c
+++ b/effects/circles/circles.c
@@ -44,4 +44,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(Circles, NULL, NULL, Init, Kill, Render);
+EFFECT(Circles, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/credits/credits.c b/effects/credits/credits.c
index 7972c63b..83097f69 100644
--- a/effects/credits/credits.c
+++ b/effects/credits/credits.c
@@ -189,4 +189,4 @@ static void Render(void) {
   swapr(cp0, cp1);
 }
 
-EFFECT(Credits, NULL, NULL, Init, Kill, Render);
+EFFECT(Credits, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/empty/empty.c b/effects/empty/empty.c
index a1854050..51a48a6e 100644
--- a/effects/empty/empty.c
+++ b/effects/empty/empty.c
@@ -27,4 +27,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(Empty, NULL, NULL, Init, Kill, Render);
+EFFECT(Empty, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/flatshade-convex/flatshade-convex.c b/effects/flatshade-convex/flatshade-convex.c
index 9c400cf4..a76e1187 100644
--- a/effects/flatshade-convex/flatshade-convex.c
+++ b/effects/flatshade-convex/flatshade-convex.c
@@ -342,4 +342,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(FlatShadeConvex, Load, UnLoad, Init, Kill, Render);
+EFFECT(FlatShadeConvex, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/flatshade/flatshade.c b/effects/flatshade/flatshade.c
index 51157a72..ef4e5b13 100644
--- a/effects/flatshade/flatshade.c
+++ b/effects/flatshade/flatshade.c
@@ -359,4 +359,4 @@ static void Render(void) {
   swapr(screen0, screen1);
 }
 
-EFFECT(FlatShade, Load, UnLoad, Init, Kill, Render);
+EFFECT(FlatShade, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/floor-old/floor-old.c b/effects/floor-old/floor-old.c
index 22118d10..2be3ef50 100644
--- a/effects/floor-old/floor-old.c
+++ b/effects/floor-old/floor-old.c
@@ -467,4 +467,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(FloorOld, Load, UnLoad, Init, Kill, Render);
+EFFECT(FloorOld, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/floor/floor.c b/effects/floor/floor.c
index b7f900c8..d991b9c4 100644
--- a/effects/floor/floor.c
+++ b/effects/floor/floor.c
@@ -259,4 +259,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Floor, NULL, NULL, Init, Kill, Render);
+EFFECT(Floor, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/game-of-life/game-of-life.c b/effects/game-of-life/game-of-life.c
index 0cf3b028..ef1baba3 100755
--- a/effects/game-of-life/game-of-life.c
+++ b/effects/game-of-life/game-of-life.c
@@ -522,4 +522,4 @@ static void Render(void) {
 #endif
 }
 
-EFFECT(GameOfLife, NULL, NULL, Init, Kill, Render);
+EFFECT(GameOfLife, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/glitch/glitch.c b/effects/glitch/glitch.c
index a6c35c94..e700bb8a 100644
--- a/effects/glitch/glitch.c
+++ b/effects/glitch/glitch.c
@@ -133,4 +133,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Glitch, NULL, NULL, Init, Kill, Render);
+EFFECT(Glitch, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/growing-tree/growing-tree.c b/effects/growing-tree/growing-tree.c
index c235f078..5889cc44 100644
--- a/effects/growing-tree/growing-tree.c
+++ b/effects/growing-tree/growing-tree.c
@@ -323,4 +323,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(GrowingTree, NULL, NULL, Init, Kill, Render);
+EFFECT(GrowingTree, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/gui/gui.c b/effects/gui/gui.c
index 02b71f1e..75f1d99b 100644
--- a/effects/gui/gui.c
+++ b/effects/gui/gui.c
@@ -137,4 +137,4 @@ static void Render(void) {
   exitLoop = !HandleEvent();
 }
 
-EFFECT(GUI, Load, NULL, Init, Kill, Render);
+EFFECT(GUI, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/highway/highway.c b/effects/highway/highway.c
index 5fcabe0c..a74ffd54 100644
--- a/effects/highway/highway.c
+++ b/effects/highway/highway.c
@@ -216,4 +216,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(HighWay, NULL, NULL, Init, Kill, Render);
+EFFECT(HighWay, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/kbtest/kbtest.c b/effects/kbtest/kbtest.c
index a1de22de..92631010 100644
--- a/effects/kbtest/kbtest.c
+++ b/effects/kbtest/kbtest.c
@@ -108,4 +108,4 @@ static void Render(void) {
   exitLoop = !HandleEvent();
 }
 
-EFFECT(KbdTest, NULL, NULL, Init, Kill, Render);
+EFFECT(KbdTest, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/layers/layers.c b/effects/layers/layers.c
index a01bdad8..90dd62c8 100644
--- a/effects/layers/layers.c
+++ b/effects/layers/layers.c
@@ -192,4 +192,4 @@ static void Render(void) {
   swapr(cp0, cp1);
 }
 
-EFFECT(Credits, NULL, NULL, Init, Kill, Render);
+EFFECT(Credits, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/lines/lines.c b/effects/lines/lines.c
index 7a7b946d..4981af9a 100644
--- a/effects/lines/lines.c
+++ b/effects/lines/lines.c
@@ -101,4 +101,4 @@ static void Render(void) {
   ProfilerStop(Lines);
 }
 
-EFFECT(Lines, Load, UnLoad, Init, NULL, Render);
+EFFECT(Lines, Load, UnLoad, Init, NULL, Render, NULL);
diff --git a/effects/main.c b/effects/main.c
index d9ddd7bc..5f28677a 100644
--- a/effects/main.c
+++ b/effects/main.c
@@ -24,11 +24,21 @@ static void StartBgTask(void) {
 }
 #endif
 
+static int VBlankISR(void) {
+  if (Effect.VBlank)
+      Effect.VBlank();
+  return 0;
+}
+
+INTSERVER(VBlankInterrupt, 0, (IntFuncT)VBlankISR, NULL);
+
 int main(void) {
   /* NOP that triggers fs-uae debugger to stop and inform GDB that it should
    * fetch segments locations to relocate symbol information read from file. */
   asm volatile("exg %d7,%d7");
 
+  AddIntServer(INTB_VERTB, VBlankInterrupt);
+
 #if BGTASK
   StartBgTask();
 #endif
@@ -39,5 +49,7 @@ int main(void) {
   EffectKill(&Effect);
   EffectUnLoad(&Effect);
 
-  return 0;
+  RemIntServer(INTB_VERTB, VBlankInterrupt);
+
+  return 0; 
 }
diff --git a/effects/metaballs/metaballs.c b/effects/metaballs/metaballs.c
index 9b2b2390..78834829 100644
--- a/effects/metaballs/metaballs.c
+++ b/effects/metaballs/metaballs.c
@@ -127,4 +127,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(MetaBalls, Load, UnLoad, Init, Kill, Render);
+EFFECT(MetaBalls, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/multipipe/multipipe.c b/effects/multipipe/multipipe.c
index 50b1cf7d..3ece1495 100644
--- a/effects/multipipe/multipipe.c
+++ b/effects/multipipe/multipipe.c
@@ -211,4 +211,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(MultiPipe, Load, UnLoad, Init, Kill, Render);
+EFFECT(MultiPipe, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/neons/neons.c b/effects/neons/neons.c
index 8616eb25..e06bb8d1 100644
--- a/effects/neons/neons.c
+++ b/effects/neons/neons.c
@@ -5,7 +5,6 @@
 #include "2d.h"
 #include "fx.h"
 #include <stdlib.h>
-#include <system/interrupt.h>
 
 #define WIDTH 320
 #define HEIGHT 256
@@ -108,7 +107,7 @@ static void UnLoad(void) {
   DeleteBitmap(screen[1]);
 }
 
-static int CustomRotatePalette(void) {
+static void CustomRotatePalette(void) {
   u_short *src = palette[0]->colors;
   CopInsT *ins = pal + 1;
   int i = frameCount;
@@ -117,11 +116,9 @@ static int CustomRotatePalette(void) {
   while (--n >= 0)
     CopInsSet16(ins++, src[i++ & 15]);
 
-  return 0;
+  return;
 }
 
-INTSERVER(RotatePaletteInterrupt, 0, (IntFuncT)CustomRotatePalette, NULL);
-
 static void Init(void) {
   EnableDMA(DMAF_BLITTER);
 
@@ -143,15 +140,11 @@ static void Init(void) {
 
   CopListActivate(cp);
   EnableDMA(DMAF_RASTER);
-
-  AddIntServer(INTB_VERTB, RotatePaletteInterrupt);
 }
 
 static void Kill(void) {
   DisableDMA(DMAF_COPPER | DMAF_RASTER | DMAF_BLITTER);
 
-  RemIntServer(INTB_VERTB, RotatePaletteInterrupt);
-
   DeleteCopList(cp);
 }
 
@@ -228,4 +221,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Neons, Load, UnLoad, Init, Kill, Render);
+EFFECT(Neons, Load, UnLoad, Init, Kill, Render, CustomRotatePalette);
diff --git a/effects/plasma/plasma.c b/effects/plasma/plasma.c
index f9ad138c..5f5edea5 100644
--- a/effects/plasma/plasma.c
+++ b/effects/plasma/plasma.c
@@ -177,4 +177,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Plasma, Load, NULL, Init, Kill, Render);
+EFFECT(Plasma, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/playahx/playahx.c b/effects/playahx/playahx.c
index 2494a0d1..63968006 100644
--- a/effects/playahx/playahx.c
+++ b/effects/playahx/playahx.c
@@ -282,4 +282,4 @@ static bool HandleEvent(void) {
   return true;
 }
 
-EFFECT(PlayAHX, NULL, NULL, Init, Kill, Render);
+EFFECT(PlayAHX, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/playctr/playctr.c b/effects/playctr/playctr.c
index 13320989..960be3a7 100644
--- a/effects/playctr/playctr.c
+++ b/effects/playctr/playctr.c
@@ -4,7 +4,6 @@
 #include <console.h>
 #include <copper.h>
 #include <system/event.h>
-#include <system/interrupt.h>
 #include <system/keyboard.h>
 #include <system/memory.h>
 
@@ -49,16 +48,14 @@ static void UnLoad(void) {
   MemFree(module);
 }
 
-static int CinterMusic(void) {
+static void CinterMusic(void) {
   if (stopped)
-    return 0;
+    return;
   CinterPlay1(player);
   CinterPlay2(player);
-  return 0;
+  return;
 }
 
-INTSERVER(CinterMusicServer, 10, (IntFuncT)CinterMusic, NULL);
-
 static void Init(void) {
   KeyboardInit();
 
@@ -83,8 +80,6 @@ static void Init(void) {
   CinterInit(module, instruments, player);
   musicStart = player->c_MusicPointer;
 
-  AddIntServer(INTB_VERTB, CinterMusicServer);
-
   ConsoleSetCursor(&console, 0, 0);
   ConsolePutStr(&console, 
                 "Pause (SPACE) -10s (LEFT) +10s (RIGHT)\n"
@@ -94,8 +89,6 @@ static void Init(void) {
 }
 
 static void Kill(void) {
-  RemIntServer(INTB_VERTB, CinterMusicServer);
-
   DisableDMA(DMAF_COPPER | DMAF_RASTER | DMAF_AUDIO);
 
   DeleteCopList(cp);
@@ -173,4 +166,4 @@ static bool HandleEvent(void) {
   return true;
 }
 
-EFFECT(PlayCinter, Load, UnLoad, Init, Kill, Render);
+EFFECT(PlayCinter, Load, UnLoad, Init, Kill, Render, CinterMusic);
diff --git a/effects/playp61/playp61.c b/effects/playp61/playp61.c
index f18858a6..4700ee10 100644
--- a/effects/playp61/playp61.c
+++ b/effects/playp61/playp61.c
@@ -4,7 +4,6 @@
 #include <copper.h>
 #include <p61.h>
 #include <system/event.h>
-#include <system/interrupt.h>
 #include <system/keyboard.h>
 #include <system/memory.h>
 #include <system/timer.h>
@@ -24,8 +23,6 @@ static CopListT *cp;
 static ConsoleT console;
 static CIATimerT *p61tmr;
 
-INTSERVER(P61PlayerServer, 10, (IntFuncT)P61_Music, NULL);
-
 static inline void putpixel(u_char *line, short x) {
   bset(line + (x >> 3), ~x);
 }
@@ -118,8 +115,6 @@ static void Init(void) {
   P61_Init(module, NULL, NULL);
   P61_ControlBlock.Play = 1;
 
-  AddIntServer(INTB_VERTB, P61PlayerServer);
-
   ConsolePutStr(&console, 
                 "Pause (SPACE) Prev (LEFT) Next (RIGHT)\n"
                 "Exit (ESC)\n");
@@ -129,7 +124,6 @@ static void Kill(void) {
   P61_ControlBlock.Play = 0;
   P61_End();
 
-  RemIntServer(INTB_VERTB, P61PlayerServer);
   ReleaseTimer(p61tmr);
 
   DisableDMA(DMAF_COPPER | DMAF_RASTER | DMAF_BLITTER);
@@ -222,4 +216,4 @@ static bool HandleEvent(void) {
   return true;
 }
 
-EFFECT(PlayP61, NULL, NULL, Init, Kill, Render);
+EFFECT(PlayP61, NULL, NULL, Init, Kill, Render, P61_Music);
diff --git a/effects/playpt/playpt.c b/effects/playpt/playpt.c
index 1bfa9408..70ad6fd2 100644
--- a/effects/playpt/playpt.c
+++ b/effects/playpt/playpt.c
@@ -4,7 +4,6 @@
 #include <console.h>
 #include <copper.h>
 #include <system/event.h>
-#include <system/interrupt.h>
 #include <system/keyboard.h>
 #include <system/memory.h>
 
@@ -12,6 +11,10 @@
 #define HEIGHT 256
 #define DEPTH 1
 
+/* XXX: Always consult this value with AmigaKlang output,
+ * otherwise you'll experience a really nasty debugging session. */
+#define AKLANG_BUFLEN 36864
+
 #include "data/lat2-08.c"
 
 extern u_char Module[];
@@ -28,14 +31,12 @@ extern u_int AK_Progress;
 void AK_Generate(void *TmpBuf asm("a1"));
 
 static void Load(void) {
-  void *TmpBuf = MemAlloc(32768, MEMF_PUBLIC);
+  void *TmpBuf = MemAlloc(AKLANG_BUFLEN, MEMF_PUBLIC);
+  Log("Generating samples, please wait...\n");
   AK_Generate(TmpBuf);
   MemFree(TmpBuf);
 }
 
-static void UnLoad(void) {
-}
-
 static void Init(void) {
   KeyboardInit();
 
@@ -181,4 +182,4 @@ static bool HandleEvent(void) {
   return true;
 }
 
-EFFECT(PlayProtracker, Load, UnLoad, Init, Kill, Render);
+EFFECT(PlayProtracker, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/plotter/plotter.c b/effects/plotter/plotter.c
index 84e9f854..365fc3d2 100644
--- a/effects/plotter/plotter.c
+++ b/effects/plotter/plotter.c
@@ -98,4 +98,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Plotter, NULL, NULL, Init, Kill, Render);
+EFFECT(Plotter, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/prisms/prisms.c b/effects/prisms/prisms.c
index c60875e3..994513da 100644
--- a/effects/prisms/prisms.c
+++ b/effects/prisms/prisms.c
@@ -342,4 +342,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Prisms, NULL, NULL, Init, Kill, Render);
+EFFECT(Prisms, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/rotator/rotator.c b/effects/rotator/rotator.c
index d203e6a9..8e5d35f5 100644
--- a/effects/rotator/rotator.c
+++ b/effects/rotator/rotator.c
@@ -310,4 +310,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Rotator, NULL, NULL, Init, Kill, Render);
+EFFECT(Rotator, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/sea-anemone/sea-anemone.c b/effects/sea-anemone/sea-anemone.c
index 751c4cd7..d519debe 100644
--- a/effects/sea-anemone/sea-anemone.c
+++ b/effects/sea-anemone/sea-anemone.c
@@ -310,4 +310,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(SeaAnemone, Load, UnLoad, Init, Kill, Render);
+EFFECT(SeaAnemone, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/shapes/shapes.c b/effects/shapes/shapes.c
index ccae1220..baca1ff1 100644
--- a/effects/shapes/shapes.c
+++ b/effects/shapes/shapes.c
@@ -140,4 +140,4 @@ static void Render(void) {
   planeC ^= 1;
 }
 
-EFFECT(Shapes, Load, UnLoad, Init, Kill, Render);
+EFFECT(Shapes, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/showpchg/showpchg.c b/effects/showpchg/showpchg.c
index 59d39a51..19cbd859 100644
--- a/effects/showpchg/showpchg.c
+++ b/effects/showpchg/showpchg.c
@@ -52,4 +52,4 @@ static void Kill(void) {
   DeleteCopList(cp);
 }
 
-EFFECT(ShowPCHG, NULL, NULL, Init, Kill, NULL);
+EFFECT(ShowPCHG, NULL, NULL, Init, Kill, NULL, NULL);
diff --git a/effects/stripes/stripes.c b/effects/stripes/stripes.c
index d5bf9587..ef137fe8 100644
--- a/effects/stripes/stripes.c
+++ b/effects/stripes/stripes.c
@@ -186,4 +186,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Stripes, NULL, NULL, Init, Kill, Render);
+EFFECT(Stripes, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/textscroll/textscroll.c b/effects/textscroll/textscroll.c
index 62f83772..af1fcc66 100644
--- a/effects/textscroll/textscroll.c
+++ b/effects/textscroll/textscroll.c
@@ -150,4 +150,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(TextScroll, NULL, NULL, Init, Kill, Render);
+EFFECT(TextScroll, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/thunders/thunders.c b/effects/thunders/thunders.c
index 9240e72a..b37a1ec9 100644
--- a/effects/thunders/thunders.c
+++ b/effects/thunders/thunders.c
@@ -449,4 +449,4 @@ static void Render(void) {
   { BitmapT *tmp = screen0; screen0 = screen1; screen1 = tmp; }
 }
 
-EFFECT(Thunders, Load, NULL, Init, Kill, Render);
+EFFECT(Thunders, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/tiles16/tiles16.c b/effects/tiles16/tiles16.c
index a0c1bb3e..f1001b57 100644
--- a/effects/tiles16/tiles16.c
+++ b/effects/tiles16/tiles16.c
@@ -203,4 +203,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Tiles16, Load, NULL, Init, Kill, Render);
+EFFECT(Tiles16, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/tiles8/tiles8.c b/effects/tiles8/tiles8.c
index a9e31de9..d8d80a0a 100644
--- a/effects/tiles8/tiles8.c
+++ b/effects/tiles8/tiles8.c
@@ -222,4 +222,4 @@ static void Render(void) {
   swapr(screen0, screen1);
 }
 
-EFFECT(Tiles8, Load, NULL, Init, Kill, Render);
+EFFECT(Tiles8, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/tilezoomer/tilezoomer.c b/effects/tilezoomer/tilezoomer.c
index 75be7f08..dc35f11d 100644
--- a/effects/tilezoomer/tilezoomer.c
+++ b/effects/tilezoomer/tilezoomer.c
@@ -269,4 +269,4 @@ static void Render(void) {
 #endif
 }
 
-EFFECT(TileZoomer, NULL, NULL, Init, Kill, Render);
+EFFECT(TileZoomer, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/transparency/transparency.c b/effects/transparency/transparency.c
index 8c443294..9b55c951 100644
--- a/effects/transparency/transparency.c
+++ b/effects/transparency/transparency.c
@@ -88,4 +88,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(Transparency, NULL, NULL, Init, Kill, Render);
+EFFECT(Transparency, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/turmite/turmite.c b/effects/turmite/turmite.c
index 7f62448b..1a2ae519 100644
--- a/effects/turmite/turmite.c
+++ b/effects/turmite/turmite.c
@@ -304,4 +304,4 @@ static void Render(void) {
   TaskWaitVBlank();
 }
 
-EFFECT(Turmite, Load, NULL, Init, Kill, Render);
+EFFECT(Turmite, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/twister-rgb/twister-rgb.c b/effects/twister-rgb/twister-rgb.c
index 653c488c..94cd0ce8 100644
--- a/effects/twister-rgb/twister-rgb.c
+++ b/effects/twister-rgb/twister-rgb.c
@@ -189,4 +189,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(TwisterRGB, NULL, NULL, Init, Kill, Render);
+EFFECT(TwisterRGB, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/uvlight/uvlight.c b/effects/uvlight/uvlight.c
index c574ffff..3eacee16 100644
--- a/effects/uvlight/uvlight.c
+++ b/effects/uvlight/uvlight.c
@@ -359,4 +359,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(UVLight, Load, NULL, Init, Kill, Render);
+EFFECT(UVLight, Load, NULL, Init, Kill, Render, NULL);
diff --git a/effects/uvmap-rgb/uvmap-rgb.c b/effects/uvmap-rgb/uvmap-rgb.c
index bb6d9843..ec25fff2 100644
--- a/effects/uvmap-rgb/uvmap-rgb.c
+++ b/effects/uvmap-rgb/uvmap-rgb.c
@@ -291,4 +291,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(UVMapRGB, Load, UnLoad, Init, Kill, Render);
+EFFECT(UVMapRGB, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/effects/uvmap/uvmap.c b/effects/uvmap/uvmap.c
index 0b30fa28..8bad6582 100644
--- a/effects/uvmap/uvmap.c
+++ b/effects/uvmap/uvmap.c
@@ -315,4 +315,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(UVMap, NULL, NULL, Init, Kill, Render);
+EFFECT(UVMap, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/weave/weave.c b/effects/weave/weave.c
index b6aa5dd9..cb0c7659 100644
--- a/effects/weave/weave.c
+++ b/effects/weave/weave.c
@@ -308,4 +308,4 @@ static void Render(void) {
   active ^= 1;
 }
 
-EFFECT(Weave, NULL, NULL, Init, Kill, Render);
+EFFECT(Weave, NULL, NULL, Init, Kill, Render, NULL);
diff --git a/effects/wireframe/wireframe.c b/effects/wireframe/wireframe.c
index d993d8fc..9ba81255 100644
--- a/effects/wireframe/wireframe.c
+++ b/effects/wireframe/wireframe.c
@@ -335,4 +335,4 @@ static void Render(void) {
     active = 0;
 }
 
-EFFECT(Wireframe, Load, UnLoad, Init, Kill, Render);
+EFFECT(Wireframe, Load, UnLoad, Init, Kill, Render, NULL);
diff --git a/include/ptplayer.h b/include/ptplayer.h
index 020101e0..ef8e9f1f 100644
--- a/include/ptplayer.h
+++ b/include/ptplayer.h
@@ -129,7 +129,6 @@ typedef struct {
   u_char mt_PattDelTime2;
 } __attribute__((packed)) PtPlayer;
 
-extern u_short PtPatternPos;
-extern u_char PtSongPos;
+extern PtPlayer PtData;
 
 #endif
diff --git a/lib/libpt/Makefile b/lib/libpt/Makefile
index 494507f1..588fb75a 100644
--- a/lib/libpt/Makefile
+++ b/lib/libpt/Makefile
@@ -4,6 +4,6 @@ SOURCES := pt.asm
 
 include $(TOPDIR)/build/lib.mk
 
-VASMFLAGS.pt += -DMINIMAL=1 -DENABLE_SAWRECT=0 -DENABLE_VUMETER=0
+VASMFLAGS.pt += -DMINIMAL=1 -DENABLE_SAWRECT=0 -DENABLE_VUMETER=0 -DJAZZCAT=1
 
 pt.o: pt.asm ptplayer.asm $(TOPDIR)/include/ptplayer.h
diff --git a/lib/libpt/README.md b/lib/libpt/README.md
new file mode 100644
index 00000000..b3fcde5d
--- /dev/null
+++ b/lib/libpt/README.md
@@ -0,0 +1,11 @@
+JazzCat does not use following commands:
+
+ * Bxy
+ * Dxy
+ * Exy
+ * 4xy
+ * 6xy
+ * 7xy
+ * 8xy
+
+You can disable them by changing `JAZZCAT` to 1 in `Makefile`.
diff --git a/lib/libpt/pt.asm b/lib/libpt/pt.asm
index ee56f06c..49582a64 100644
--- a/lib/libpt/pt.asm
+++ b/lib/libpt/pt.asm
@@ -2,17 +2,15 @@
         xdef    _PtRemoveCIA
         xdef    _PtInit
         xdef    _PtEnd
-        xdef    _PtSongPos
-        xdef    _PtPatternPos
+        xdef    _PtData
         xdef    _PtEnable
         xdef    _PtE8Trigger
 
         section '.text',code
 
+_PtData         set     mt_data+mt_chan1
 _PtEnable       set     _mt_Enable
 _PtE8Trigger    set     _mt_E8Trigger
-_PtSongPos      set     mt_data+mt_SongPos
-_PtPatternPos   set     mt_data+mt_PatternPos
 
 _PtInstallCIA:
         movem.l d2-d7/a2-a6,-(sp)
diff --git a/lib/libpt/ptplayer.asm b/lib/libpt/ptplayer.asm
index ffec6b1e..cffbe33a 100644
--- a/lib/libpt/ptplayer.asm
+++ b/lib/libpt/ptplayer.asm
@@ -566,7 +566,7 @@ mt_generate_period_table:
 ;
 ; See: https://eab.abime.net/showpost.php?p=1465997&postcount=132
 
-        rem
+        ifeq JAZZCAT
 mt_generate_vib_sine_table:
 	move.l	d2,-(sp)
 
@@ -595,7 +595,7 @@ mt_generate_vib_sine_table:
 	dc.w	$b400,$c500,$d400,$e000,$eb00,$f400,$fa00,$fd00
 	dc.w	$ff00,$fd00,$fa00,$f400,$eb00,$e000,$d400,$c500
 	dc.w	$b400,$a100,$8d00,$7800,$6100,$4a00,$3100,$1800
-        erem
+        endc ; JAZZCAT
 
 ;---------------------------------------------------------------------------
 
@@ -669,9 +669,9 @@ _mt_init:
 
 	;Antiriad - generator code
 	bsr	mt_generate_period_table	;Create period table
-        rem
+        ifeq JAZZCAT
 	bsr	mt_generate_vib_sine_table	;Create sine vibrato table
-        erem
+        endc ; JAZZCAT
 	;Antiriad - end
 	;Fallthrough to mt_reset
 
@@ -1559,13 +1559,14 @@ mt_checkfx:
 	move.w	fx_tab(pc,d0.w),d0
 	jmp	fx_tab(pc,d0.w)
 
-; [cahir] disabled commands
+        ifne JAZZCAT
 mt_arpeggio set mt_nop                  ; 0 x y
 mt_portaup set mt_nop                   ; 1 x y
 mt_vibrato set mt_nop                   ; 4 x y
 mt_vibrvolslide set mt_nop              ; 6 x y
 mt_tremolo set mt_nop                   ; 7 x y
 mt_e_cmds set mt_nop                    ; E x y
+        endc ; JAZZCAT
 
 fx_tab:
 	dc.w	mt_arpeggio-fx_tab	; $0
@@ -1888,10 +1889,11 @@ checkmorefx:
 .1:	move.w	morefx_tab(pc,d5.w),d0
 	jmp	morefx_tab(pc,d0.w)
 
-; [cahir] disabled commands
+        ifne JAZZCAT
 mt_posjump set mt_pernop        ; B x y
 mt_patternbrk set mt_pernop     ; D x y
 mt_e_cmds set mt_pernop         ; E x y
+        endc ; JAZZCAT
 
 morefx_tab:
 	dc.w	mt_pernop-morefx_tab,mt_pernop-morefx_tab,mt_pernop-morefx_tab
@@ -1917,12 +1919,13 @@ moreblockedfx:
 	move.w	blmorefx_tab(pc,d6.w),d0
 	jmp	blmorefx_tab(pc,d0.w)
 
-; [cahir] disabled commands
+        ifne JAZZCAT
 mt_arpeggio set mt_nop          ; 0 x y
 mt_fineportaup set mt_nop       ; 1 x y
 mt_posjump set mt_nop           ; B x y
 mt_patternbrk set mt_nop        ; D x y
 blocked_e_cmds set mt_nop       ; E x y
+        endc ; JAZZCAT
 
 blmorefx_tab:
 	dc.w	mt_nop-blmorefx_tab,mt_nop-blmorefx_tab
@@ -1938,7 +1941,7 @@ blmorefx_tab:
 	dc.w	mt_setspeed-blmorefx_tab		; $F
 	endc	; !MINIMAL
 
-        rem
+        ifeq JAZZCAT
 mt_arpeggio:
 ; cmd 0 x y (x = first arpeggio offset, y = second arpeggio offset)
 ; d4 = xy
@@ -2005,7 +2008,7 @@ mt_fineportadn:
 	tst.b	mt_Counter(a4)
 	beq	do_porta_down
 	rts
-        erem
+        endc ; JAZZCAT
 
 mt_portadown:
 ; cmd 2 x x (add xx to period)
@@ -2076,7 +2079,7 @@ mt_toneporta_nc:
 .5:	move.w	d2,AUDPER(a5)
 .6	rts
 
-        rem
+        ifeq JAZZCAT
 mt_vibrato:
 ; cmd 4 x y (x = speed, y = amplitude)
 ; d4 = xy
@@ -2130,7 +2133,7 @@ mt_vibrato_nc:
 	; increase vibratopos by speed
 	add.b	d4,n_vibratopos(a2)
 	rts
-        erem
+        endc ; JAZZCAT
 
 mt_tonevolslide:
 ; cmd 5 x y (x = volume-up, y = volume-down)
@@ -2139,7 +2142,7 @@ mt_tonevolslide:
 	pea	mt_volumeslide(pc)
 	bra	mt_toneporta_nc
 
-        rem
+        ifeq JAZZCAT
 mt_vibrvolslide:
 ; cmd 6 x y (x = volume-up, y = volume-down)
 ; d4 = xy
@@ -2214,7 +2217,7 @@ mt_tremolo:
 	; increase tremolopos by speed
 	add.b	d4,n_tremolopos(a2)
 	rts
-        erem
+        endc ; JAZZCAT
 
 mt_volumeslide:
 ; cmd A x y (x = volume-up, y = volume-down)
@@ -2250,7 +2253,7 @@ set_vol:
 	move.w	d0,AUDVOL(a5)
 	rts
 
-        rem
+        ifeq JAZZCAT
 mt_posjump:
 ; cmd B x y (xy = new song position)
 ; d4 = xy
@@ -2263,7 +2266,7 @@ jump_pos0:
 	move.w	d7,mt_PBreakPos(a4)
 	st	mt_PosJumpFlag(a4)
 	rts
-        erem
+        endc ; JAZZCAT
 
 mt_volchange:
 ; cmd C x y (xy = new volume)
@@ -2280,7 +2283,7 @@ mt_volchange:
 	move.w	d4,AUDVOL(a5)
 	rts
 
-        rem
+        ifeq JAZZCAT
 mt_patternbrk:
 ; cmd D x y (xy = break pos in decimal)
 ; d4 = xy
@@ -2300,7 +2303,7 @@ mt_patternbrk:
 
 mult10tab:
 	dc.b	0,10,20,30,40,50,60,70,80,90,0,0,0,0,0,0
-        erem
+        endc ; JAZZCAT
 
 mt_setspeed:
 ; cmd F x y (xy<$20 new speed, xy>=$20 new tempo)
@@ -2321,7 +2324,7 @@ mt_setspeed:
 	move.b	d0,CIAB+CIATAHI
 	rts
 
-        rem
+        ifeq JAZZCAT
 mt_e_cmds:
 ; cmd E x y (x=command, y=argument)
 ; d4 = xy
@@ -2577,7 +2580,7 @@ mt_funk:
 	move.w	d0,n_funk(a2)
 	bne	mt_updatefunk
 .1:	rts
-        erem
+        endc ; JAZZCAT
 
 mt_updatefunk:
 ; d0 = funk speed
@@ -3164,10 +3167,10 @@ mt_TuningM1	rs.w	36
 ; Antiriad - end of periodtable
 
 ; Antiriad - vibrato sine table
-        rem
+        ifeq JAZZCAT
 mt_VibratoSineTable	rs.b	16*64
 mt_VibratoSineTable_End	rs.b	0
-        erem
+        endc ; JAZZCAT
 ; Antiriad - end of vibrato sine table
 
 mt_chan1	rs.b	n_sizeof
diff --git a/system/effect.c b/system/effect.c
index 3730aa09..450362d2 100644
--- a/system/effect.c
+++ b/system/effect.c
@@ -94,7 +94,7 @@ void EffectRun(EffectT *effect) {
     int t = ReadFrameCounter();
     exitLoop = LeftMouseButton();
     frameCount = t;
-    if (effect->Render)
+    if ((lastFrameCount != frameCount) && effect->Render)
       effect->Render();
     lastFrameCount = t;
   } while (!exitLoop);