Killing Floor 1.0

Killing Floor is a Co-op Survival Horror FPS set in the devastated cities and countryside of England after a series of cloning experiments for the military goes horribly wrong. You and your friends are members of the military dropped into these locations with a simple mission: Survive long enough to cleanse the area of the failed experiments! Cooperative gameplay for up to six players against multiple waves of specimens. Persistent Perks system, allowing players to convert their in-game achievements into permanent improvements to their character's skills and abilities. Over 170 Steam Achievements, including “Dignity for the dead” for killing 10 enemies feeding on dead teammates' corpses and “Hot Cross Fun” for finishing off 25 burning enemies with a Crossbow.