100 hours can be quite a long time for this game. Playing normally on my first playthrough, I hardly came up to half of that. On my second and any repetitive runs after that, I only managed to get up to 70 hrs clocked on a save, so suffice to say, this may be one of the last trophies you'll end up getting. Apparently there are two clock systems that are simultaneously running through the game: the one that you can see in the menu, or on the save file, and the one that is saved within the System Data file. You can't necessarily see the one in the System Data, but I have an instance where saving the game randomly awarded it when the player's hours only read 96.