Tony Stark/Iron Man with Hulkbuster Armor is the final boss in Hulk's story. In the game, Stark is sent by a false "Nick Fury" to stop Hulk. The Hulk then defeats him, only to have Captain America arrive and prepare to tell the truth. Before he can, however, Thor crashes into the ground, scattering all heroes present.
This armor was designed specifically to fight against the Hulk. When Iron Man is first encountered, he is at Level 35. He fights using punches, repulsor rays, missles, unibeams, and a stomp attack. He usually attacks with punches, which can be deflected, blocked, or dodged, though he can break blocks. His unibeam and repulsors cause unblockable laser burn. From a long range, he can shoot missles, which can be deflected back, or unibeams, which must be dodged. He often finishes these ranged attacks by lunging towards Hulk with a heavy stomp.
Eventually, the Hulk will damage Iron Man enough to knock off his Hulkbuster Helmet, forcing him to call in a massive laser strike and finish Hulk. Crosshairs will encircle Hulk, slowly closing in on the green behemoth. There is no way to defend, dodge, counter, or survive this attack. Once the crosshairs come together and allign themselves on the Hulk, you lose the fight immediately. Special moves are strongly recommended for this final phase of the fight, so be sure you have plenty of rage packs.