The rule is simple. Tilt the ball and avoid the enemies. More you tilt and faster you move, more points you earn. There are 7 specials items available during the game with indicated color rings. With special items these effects will last for several seconds:
Orange = Move faster.
Green = Protected with shield.
Blue = Stop the enemies.
Light Blue = Get smaller.
Red = Eliminate all.
Yellow = Become invincible. Hit the enemies and earn points!
Gray = Random effect.
With Game Center features enabled you can compete you scores with players around the world.