Voodoo Extreme, Tripwire was approached by the mod's original designer to create a port of the survival-horror shooter that would run on Red Orchestra. Tripwire decided Killing Floor could do better and offered to purchase the rights to the game and help the original team bring an upgraded version to Steam in standalone form.
Like Left 4 Dead, Killing Floor -- which originally released in 2005 -- features enemy hordes making violent rushes to halt player advancement. The game will feature six-player co-op play, nine different monster types (varying from physical predators to weapon wielding foes) and a stockpile of different weapons for players to use. Killing Floor also includes a persistent perk system allowing players to set themselves apart from other survivors with skill and ability upgrades -- something we think L4D's Louis would have loved to have, to help fight off his most traumatic attack. No release date has been announced.