Killing Floor is a cooperative FPS developed by Tripwire Interactive Gameplay consists of a single game type, single- or multi-player fights waves of zombie-like specimens, with each wave becoming increasingly more challenging. As you clear down the waves of enemies the level concludes with a big bad “boss” specimen called the “Patriarch” A wave is completed when all the specimens are dead. You choose where to run and fight with up to six players in cooperative battle mode. Change difficulty settings, number of enemy waves, or specify which creatures compose the waves. You can create your own levels using the editor included. Plenty of weapons to chose from, including melee weapons, shotguns, rifles and pistols. Cash can be accumulated through killing specimens, surviving waves, from other players, and selling acquired weapons. Money can then be used for weapons, supplies, and ammunition. Zed time lets you see gory kills, such as headshots, in slow-mo, even in multiplayer mode. It can also be used to gain an advantage and aim shots for max effect.