Its a bubble eat bubble world out there. The only way to survive is to become the biggest. Absorb as many bubbles as you can as quickly as possible. Remember you can only absorb bubbles that are smaller than you, so don't go to close to the big ones!
When the game starts you have 3 seconds of invulnerability. Use your mouse to control the bubble, absorb bubbles smaller than you, and try to clear the screen in as fast a time as possible.