Killing Floor CD Key is said to be a cooperative shooter game that is to be played from the first person perspective. Tripwire Interactive is its publisher and developer. It was in 2005 that it got launched as 2004 Unreal Tournament mod. On 14th May 2009, MS Windows retail release was done and on 5th May 2010 for OS X. In November 2012, on Steam platform, Linux version got launched. It runs on Unreal Engine 2 and is both a single and multiple player game. There are two game types in the gameplay, where the player is required to combat specimens that are zombie like. As the game progresses, each wave tends to become all the more difficult until the battle is against Patriarch, the ‘boss’ specimen. For every kill, the players stand to earn in-game money. In between he can have armor, additional weapons like pipe bombs, kaanas, shotguns, flamethrowers, etc. to be bought and sold.
Every game is to be configured for altering the different wave’s difficulty and length. Once it got released, it became a commercial hit and was among Steam’s top selling game, selling over 3 million copies. Killing Floor is also credited with having won numerous awards like the 2009 Best PC game in Reader Choice Awards held by Voodoo Extreme and others.