Zombies are all the rage these days, movies, games, TV series you name it, zombies are in it. One of the more recent Zombie games that had a decent amount of success was Killing floor and if you havent tried it yet, then heres your chance to do it for free.
Tripwire Interactive are offering Killing Floor free to play to everyone for a long weekend, starting on Thursday 8 December 2011 and running through to Sunday 11 December. This will give everyone who has not yet played the game a chance to try it out completely free!
There also seems to be a bit of a surprise that they are getting the community to figure out. The image below is on their steam group and you can head over to their steamgroup to look for more clues too. http://steamcommunity.com/games/KillingFloor