mhh... the gravity... Well first I created a double parameter, that saves the y position (called yPosition and one, that saves the y-Speed (called ySpeed). then i rewrited the setLocation method to: setLocation(int x, double y){ super.setLocation(x,(int)y); yPosition=y;} and I added a method double getYPosition(){return yPosition;} and in my act-method is written: setLocation(getX(),getYPosition()+ySpeed); Then all I have to do for the gravity is raising ySpeed for 0.1 And if the up-key is pressed, I subtract 0.2 If you although want an x-move you have to do the same with x.

Wow! The collision check is perfect. How you made this?

Nice made! I just got bored when I had ~1500 points, so I let the enemy shoot me down. Maybe you want to add this: When two bullets (or missiles?) hit each other, they vanish. With this, you can block enemy bullets and he can block yours. I'd like it, just think about it. ;)