Few games enjoy the longevity of Killing Floor. Released in 2009, Tripwire Interactive's "co-op survival horror" enjoys relevancy in no small part due to Developer support. Killing Floor enjoys updates and events throughout the year, and the spookiest holiday can't be forgotten. For the second year running, KF is unleashing the Hillbilly ZEDs on your British Special Forces until November 3rd. The Redneck-themed mutants/clones are far wackier than your standard bunch of zombies; but this particular horror is a double feature.