For some silly reason, the Amnesia DLC doesn't let you save. You either beat it in one go or you lose all progress. It's pretty dumb considering this is an intense survival horror game with a heavy emphasis on puzzles.
I believe Valve's clock only updates when a game is "completed". But the other clocks posted earlier in this thread have their own estimations of earlier unlocks based on total play.
Having the timer only count completed games doesn't make much sense, since Killing Floor is a multiplayer game and can't really be completed. Also, some games would take significantly longer to complete than others.
This comment was edited on Apr 17, 2011, 01:40.