I guess the issues he's having is you can only check for collision once a tick and the behavior is still moving between that time, so you never get 100% perfect calculations that way. I guess he needs 100% accuracy for some reason. I would suggest using event sheet movement, but I'm assuming the reason is the pixel offset randomly? I did not know that - not that there would be any chance of my none CPU-like brain to notice such a thing at runtime. But could explain some wierdness I may or may not have experienced in the past with overlapping but strugged off.