There is a harder difficulty you can unlock in Dead Space 2 for the PS3 and Xbox 360 called Hardcore Mode.
Hardcore Mode is essentially the same difficulty as the Zealot difficulty as far as damage taken and enemy health, but it has a few twists that make it harder. You can’t use New Game+, you can only restart from a saved game, and you can only save three times throughout the entire game.
To unlock Hardcore Mode, you just need to beat the game on any difficulty.
