Play as a cell, grow and mulitply to produce friendly cells to help kill the bad ones. I got the idea for this whilst watching evolution, not that it's anything like evolution but there you go.
The gameplay is pretty simple, collect the little yellow cells to help you grow and shoot the other cells (using the mouse) before they get to you. Select either WASD or Arrow key controls from the main menu, i know some people don't have wasd keyboards so the option is there to switch.
Also, the highscores are a bit weird, in that you have to remember to press "submit" not done as "done" will close the highscores, causing you to lose your score!