Hulkbuster Iron Man Suit
Play "Iron Man" in the Xbox 360, pause the game and save. Quit and eject "Iron Man" and insert "The Incredible Hulk." When you go to the "Character Selection" screen, you will automatically be able to play as Iron Man in his Hulkbuster suit.
Tougher Skin
Press "Right," "Right," "Y," "X," "A" and "Left" at any point to activate this cheat. It keeps the Hulk from taking any damage.
Ironclad and Abomination
Fight the U-Foes and use one as a human shield. If a teammate accidentally kills the U-Foe, you can play as Ironclad. After that happens, defeat the Abomination to select him as a playable character at the "Character Selection" screen. This also unlocks two new gamer pictures for your Xbox 360 profile.
Quick Hits
Find five of the 15 hidden comic book covers to play as Classic Hulk. The books make a chime when you are close to them. Destroy at least one building in each New York neighborhood to play as the Maestro. The fastest way to destroy buildings is to continuously attack the foundations. Beat the game to play as Joe Fixit. Do all 15 of the jump challenges to play as the Professor Hulk, which is essentially the Hulk but with Bruce Banner's personality. Smash at least 10,000 objects to play as Gray Hulk.