Multiplayer compatibility issues

[BenCheung0422]

Background

Originally the game was just designed to be a solo game, so many factors involved in multiplayer system have not been really considered. This is an important problem that must be solved before implementing the multiplayer system, like I have mentioned in #711.

---

The following is the list of all relevant issues and may be updated. Only the ones that can cause multiplayer balancing or behaving problems (not general issues) are tracked here.

[Makkkkus]

This issue just references some other issues and brings no new suggestions. I will therefore close this.

Multiplayer support organised in the "Multiplayer support" project.