Dark Souls is already a hard game, but for those that manage to complete the game there's the option to restart, keeping all your gear and levels. There is a catch however - the game gets even more difficult, with enemies hitting harder and taking more to beat. But even New Game Plus has a limit as to how much replayability it adds to the game. Sure, you could argue that anything after this point would be a bit superfluous, considering the hundreds (if not thousands) of hours that are likely to have already put in by this point, but that's making the assumption that New Game+ is the way that people would want to continue. Something like an unlockable mode - say a wave based co-op mini-game - would be a fantastic addition, rather than the way it is right now, where you have to scour item descriptions and weapon boxes to take in more the remaining story.