Here at modDB you can read an exclusive Killing Floor interview, an Unreal 2K4 modification.
!Bryan! (modDB): There appears to be at least a dozen zombie modifications in development. How do you plan on making sure yours is original, refreshing, and creative?
Alex (Killing Floor): I can't promise that it will be. But right off the bat, I’d say we have among the most detailed environments available in any zombie mod, and a truly massive amount of new content (This is a total conversion and next to ZERO original UT2k4 assets are being recycled). So from a game play standpoint, you run, you gun, and you and your team shoot zombies. It's been done. Artistically, you probably haven't seen much like this. And I’m counting on that to haul ass for the technically banal game play.