Beat all your rivals to pass to the next level. Some of them need more than one hit to fall, and you just have 90 seconds per level! The orange players are special, they give you more size and speed; others give you extra balls. The goals are not necessary to pass to the next level, but they give you extra points.
Move the mouse to catch the ball with your player (you don't need to click: the player will kick the ball automatically).