You are playing Filler 2
Filler is back with improved graphics, improved physics, three difficulties, and 100 challenges to keep you busy! Your goal is still the same: fill 2/3 of the level to advance. For added strategy, play the game on Normal and press space to freeze the balls in place. Mouse down to create a filler ball. It will continue to grow until it hits a bouncy ball (ouch!) or another filler ball. Press space to freeze all the bouncy balls (drains your freeze).