This is Easter egg in Killing Floor game.




Killing Floor is a Co-op Survival Horror FPS taking place in the devastated cities and countryside of England, after a series of cloning experiments for the military goes horribly wrong. You and your friends are members of the military, dropped into these locations with a simple mission: survive long enough to cleanse the area of the failed experiments. The only problem is, these experiments arent waiting to be taken out theyre coming for YOU!
Key features: * Co-op game mode for up to six players obliterating multiple waves of specimens * Persistent Perks system, allowing players to convert their in-game achievements into permanent improvements to their characters skills and abilities * Over 40 Steam Achievements, including Dignity for the dead for killing 10 enemies feeding on dead teammates corpses and Hot Cross Fun for finishing off 25 burning enemies with a Crossbow. * Watch those crucial and violent creature deaths in slomo ZEDtime, even in multiplayer * Solo game mode for offline play * 9 different monster types trying to eat your face off, armed with everything from teeth and claws, through to chainsaws, chainguns and rocket-launchers * 12+ weapons for the players to chose from, ranging from knives and fire-axes up to pump shotguns, rifles and a flamethrower * Add in a welder, medical tools and body armor to help the players survive * Players choose which Perks to play with, so they can best balance out a co-op team to survive the horrors * Open, non-linear play areas: choose when and where to fight or run; weld doors closed to try and direct the monster horde * Fully-configurable, allowing players to change things as simple as the difficulty level or number of creature waves, or go so far as to set up their own favorite waves of monsters * Support for Steam Friends and other Steamworks features * Includes SDK for the creation of new levels and mods (less info)