The Martian Slayer

Play as Sergeant Romero Carmack who must escape the facility by killing all the Martians who have invaded the facility, stealing the weapons, and killing all the workers.     

In order to get out of the facility, you must collect the 3 key cards spread throughout the level.     

To collect the 3 key cards, you need to explore the facility and kill any Martians insight cause it Slay or be Slayed!