The objective of the game is to guide the worm to eat other microorganisms and evolve. While many of these microorganisms are defenseless, there are certain types of multicellular organisms that will attack the worm. To defeat these enemies, the player must guide the worm to eat the glowing cells that make up the bodies of the enemies. Different types of enemies have different ways of attacking the worm, so the player must determine a particular strategy to defeat each one.

Early on in the game, the worm swims in brighter, shallow waters. To progress into deeper waters (where more difficult enemies dwell) the worm must eat red microorganisms. Alternatively, blue microorganisms enable the player to backtrack. Players are capable of customizing the physical appearance of their organism based on the gameplay.[/b]
Game can be found here,

It was just released on the ps3 on the 22nd as a download from the store, best $7 I ever spent ( it's a hell of alot better then the original flash one ) The game has a "soothing" soundtrack and each time you eat the organisms they all make different sounds as they go through you adding the music. Alot of people find this game calming if your stressed or just want something to pass some time with.