It's your job to clean up a microbe-infested world (pictures)

Play as Mr. Bulb and fire your projectiles to destroy the monster microbes in a grimy world.

Try to get the most stars possible in each level so you can unlock new worlds.

The perfect shot on top of this level is to bounce the projectile and hit each monster microbe.

Some levels like this one require that you unleash the spiked barrels at the top to kill the monster microbes on the bottom.

As you play, you'll find puzzle pieces that add to a mysterious puzzle you can view from the main menu. There's little in the way of explanation for what it all means.