In Marvel: Ultimate Alliance 2 for the PS3 and Xbox 360, you can unlock Legendary mode, which is the hardest difficulty in the game.
To unlock Legendary mode, you’ll need to beat the game on Heroic or Super Heroic. Once you do that, go to the briefing console, and it will ask you if you want to start a new game on Legendary mode with all of your current heroes, levels, and abilities.