Paintball games mimic the true principle of paintball. And this principle, what is it? In fact, you have weapons that look like real but which has actually bullets filled with paint. Paintball is played in teams or solo, and you need to hit your opponents with your paint balls. When an opponent is hit, he is eliminated. The last remaining player is the winner.
In paintball games, you will also find airsoft guns games which have no paint.
In any case, beat your opponents and make sure that you are the only left.