Indie FPS still selling well after 2009 standalone release
Released as an Unreal Tournament 2004 mod and converted in 2009 for re-release as a standalone indie shooter, Killing Floor is not a new game.
But independent developer and publisher Tripwire has told Gamasutra that sales are still strong.
Over 1.1 million copies of the game have sold, along with 2 million DLC packs.
The Georgia-based Tripwire has sold 2 million copies of its PC titles, which include Red Orchestra and the South American first person melee game Zeno Clash.