Test on low end target hardware. Make measurements in an easy and consitently repeatable way. Check if your project actually has any performance issues. Check i...
True. It's actually more complex, because you can pick before the collision check and keep collision cells, but only the first objectType in the collision check: SpritesA on Collision with SpritesB. Only picking SpriteB instances disables collision cells for that conditions, all other picking is fine.