Survive the endless waves of Bacteria and exterminate as many of them before you die.
Really good, but the high scores jump around and make it almost impossible to leave comments on the Arcade. To help the game run at low framerates, I might suggest using the event:
On start of layout: set minimum framerate to x,
where x is 1.5 times a bullet's length divided by its speed. That should make sure the game runs as fast as possible without missing collisions when there's a lot of enemies on-screen (SOME hits to the player may not register, but he needs all the help he can get!).
Otherwise, it's just perfect.