Well, you get to be an artist and use the blood of your enemies to paint the walls with it.
When you paint your path through the maze, you must find keycards to unlock and destroy a processing computer. After destroying it you will be transfered to the next more complex maze and so on until the last maze where you must destroy the main computer freak and alien boss.
There are many useful power-ups in the maze! Find, collect and use them against your enemies. But be careful, there are also several power-downs.
For every killed alien you get money which can be spent in shops for buying better arms and more ammo!