Killing floor is one of those games that appeared thanks to mods (KF was a mod for Unreal tournament). Killing Floor is really such a simple idea, but how good and fun it is. I'm a big fan of games where mutants of different types are presented as enemies and each type has its own name, attacks, etc. and besides, I'm a big fan of metal and rock, KF's soundtrack sounds quite dated and simple, but it still rocks. I would give the game 10/10, however, it seems to me that during the KF1 days Tripwire's hands grew in a different place than with a flashlight? what about the loading screen design? Why do zeds sometimes go into Michael Jackson mode? At first I blamed the engine, but then I remembered that the reboot of DmC, Killing floor 2 and other games that look much better were developed on the same engine (UE3). But overall, Killing floor is truly a gameplay masterpiece.