It's a volleyball game. There are two players - if you are playing a one player game, then you are the player on the left. Win points by making the ball land on your opponent's side of the court. The first player to six points wins! You can touch the ball as many times as you like, and you can win a point even if you don't serve. You can play against a friend, or challenge the five computer opponents in one player mode. For more info, read the One Slime FAQ.