Changes from the first game include new perks and weapons, as well as a VS Mode where a second team of players controls the Zeds. A PlayStation 4 installment was released on the same day, and a port to the Xbox One was made available on August 28, 2017. Killing Floor 2 came out on April 21st 2015 as a Steam early access game, and saw a full retail release on November 18th in 2016. The game is developed on a modified Unreal Engine 3. Killing Floor 2 (also referred as KF2) is a first-person survival coop shooter video game developed and published by Tripwire Interactive for PC and Linux.