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!.Killing floor is now 75% OFF on steam go get it now.

• 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 
• Slow-motion “ZEDtime” to better watch those crucial and violent creature deaths, even in multiplayer 
• Solo game mode for offline play 
• Ten different monster types trying to eat your face off, armed with everything from teeth and claws, to chainsaws, chain-guns and rocket-launchers 
• 33+ weapons for the players to chose from, ranging from knives and fire-axes to pump shotguns, rifles and a flamethrower 
• Equip your team with welders, medical tools and body armor to help your odds of survival 
• Choose which Perks to play with to best balance out your co-op team against the horrors 
• Open, non-linear play areas: choose when and where to fight — or run; weld doors closed to direct the monster horde down alternate corridors 
• Fully-configurable, allowing players to change the difficulty level, number of creature waves, or even set up their own favorite waves of monsters 
• Support for Steam Friends and other Steamworks features 
• Includes Windows-only SDK for the creation of new levels and mods