I just completed Dead Space for the second time, this time on Impossible difficulty. It was hard but nowhere near as difficult as the top difficulty in other games. I had relatively no trouble other than the infirmary part of the USM Valor. The Hive Mind was MUCH easier than I thought it was going to be. One issue I had with the Impossible difficulty setting had nothing to do with the gameplay itself but DLC. If you didn't know, the DLC in Dead Space is primarily upgraded weapon and armor kits. You can basically buy your way out of beating Impossible which I think kind of eliminates the point. Well, I'm off to play Dead Space a third time (this time with just the Plasma Cutter).