The catch, as reported on the official Ion Storm forums, is that a bug in the game resets the difficulty level to Normal level if you save and load your position in-game. The word from one of the Thief developers is that: 'We're looking into it.Can't say anything more for now, and there aren't any guarantees... but the find isn't being ignored.' The PC version should be relatively easy to patch, but fixing the Xbox version would be trickier, perhaps requiring a full recall (Microsoft doesn't allow the Xbox Live service to be used for anything other than patches that affect online play.)