Andromeda

You play as the bacterial Andromeda, which has successfully invaded a multi-cellular organism. Your goal is to stay alive as long as possible, by avoiding the surrounding organism's immune system. While inside the organism, your goal is to eat as much tissue as possible, consuming fat cells, blood vessels, and even mutant cells. For every 5000 points consumed, the bacteria will increase in size. It can even enlarge to destroy the immune system cells which seek to eliminate it. Fat cells will regenerate slowly, but arterial vessels will heal immediately, thus preventing arterial bleed.

There are a total of 7 difficulty levels of play. At higher levels, the immune system will attack sooner and more frequently. The player starts with 3 lives, and if all are lost, it's game over.