I just started to get into the BGE, and for learning some basics i started with a Pong clone. The movement of the players, counting of points, adding some eyecandy and sounds, it all went well and was fun. But now used a constrain logic brick to limit the ball z movement to prevent it from bouncing on the floor and to prevent to play the hit-sound every time it touches the floor. And here is my first problem: since i use this actuator, the bounding geometry of the ball seems to grow everytime it collides (first time hit bat, second time hit air in front of bat and so on). Second problem is that the balls speed is totally uncontrolled. there are times it slows down after a collision, the other time it goes up and away with the speed of light.
I attached the .blend-file, so if someone could tell me my mistake, i would be thankful.
pong.blend (257 KB)