It could be all sorts of things, without seeing the code it'll just be a case of wild guesses! Can you upload the scenario with the source so we can see what's going on?

here are the two player and bullet classes(each seperated by braces)(this one works and shoots)

I think your problem is: Because Domo is a BulletBill, when Player fires a Domo, the Domo still intersects the Player next round -- when the Player looks for an intersecting BulletBill. It finds the Domo and removes it from the world, so each Domo will only be in the world for one frame before it hits the Player who fired it! You want: In fact, I'd question whether you need four classes at all -- I think two will do, one player class and one bullet class. Rather than copy and paste your code and tweak it (which means every time you want to change the bullets, you need to do it in two places!), have one player class that takes its keys as parameters to the constructor (or have set methods), and one bullet class, but follow up on the getOneIntersectingObject call by casting the bullet class and asking who fired it (to then check and make sure each player is only hit by bullets from *other* players).