Tripwire Interactive announces The Killing Floor Twisted Christmas, a special event to run from December 14 through January 4 offering free content including new level, new achievements, a special unlockable character for the co-op survival/horror game. The event will also include a Team Fortress 2 crossover: "As part of the Twisted Christmas event the worlds of Killing Floor and Team Fortress 2 are colliding in a special promotion. Everyone who owns both Killing Floor and Team Fortress 2 will now get a playable red or blue "The Pyro" character from TF2 recreated in the Killing Floor art style! But wait there's is more - everyone that owns TF2 and either already owns or purchases Killing Floor before the event ends will receive a special item in Team Fortress 2: Mr Fosters Gasmask and Tie equippable on the Pyro! This item is only available until the end of the Twisted Christmas event on January 4th so act now!" This trailer shows off some of what to expect.