Tripwire Interactive announces that preloads of Killing Floor are underway through Steam in advance of the free-play weekend for Tripwire Interactive's zombie shooter that gets underway tomorrow. They describe the new content being added to the game, which is previewed on IGN, and say the game will be on sale for 25% off over the weekend: "The Free Weekend will run from Thursday 22nd through Sunday 25th October and will allow anyone to play the full game, including all the additional free content, all weekend. This includes the latest “Level Up” content pack and the Defence Alliance mod, both being released on Thursday. It also includes a 25% discount on buying Killing Floor over Steam for the duration of the weekend."