ok so this is cool, they are giving out free content pack to any killing floor game owners and a free weekend!
Roswell, GA, 14th October 2009: We are pleased to announce the “Level Up” Free Content pack for Killing Floor. This massive new content pack will be our largest free content pack to date and will be available October 22nd for anyone that owns Killing Floor. To celebrate and to allow as many people as possible to try it out, we will also be running a free weekend on Steam from Thursday October 22nd through Sunday October 25th. Full details on the pack will be available in a detailed preview article on IGN on Tuesday October 20th, so watch for that one. Also watch our web site (www.killingfloorthegame.com) for more details on this over the next few days!
Killing Floor is now available in stores across North America and Europe as well as digitally on Steam (www.steampowered.com).
Article from Gamersyndrome.com