This approach is initially effective: when Downey's Stark is milking his newfound superhero status and messing with stuffed shirt politicos, Iron Man 2 has the humor and ramshackle charm of a Judd Apatow movie. The charm starts wearing off, though, as director John Favreau and writer Justin Theroux crank up the Stark angst with each passing scene. First, it's shown that the palladium in Stark's arc-reactor heart implant is quickly poisoning his blood, then Defense Department goons start demanding Stark turn over the Iron Man technology, then the arrival of sexy young legal aid Scarlet Johansson complicates Stark's relationship with Pepper Potts, then, to top it all off, it turns out that Tony has a bunch of unresolved issues with his dead father, Howard (played from beyond the grave by Mad Men's John Slattery in the casting coup of the year). And all of this before rogue Russian physicist Mickey Rourke shows up in his own Iron Man suit to get revenge on the Stark family for long past crimes. None of these elements can get the screen time they need to really develop, and so they sort of drift by, unconnected to any greater narrative arc while Tony gets more erratic and sullen. This pattern continues until the inevitable moment when all the audience wants is for something to blow up already. Eventually, things do blow up, and when they do, it's pretty impressive; certainly an upgrade over the perfunctory climax of the first film, but as in the first film, the villain is so undeveloped that the stakes and impact of the conflict are muted.
Iron Man 2 wants to be a real movie, not just a comic book exercise, but the necessities of the comic book genre end up leaving most of the character interaction undercooked. Particularly, the interplay between Stark and Gwyneth Paltrow's Pepper Potts, which was the emotional engine of the first movie, feels muddled and scattershot here. Their interaction has a loose, improvisational feel, but that authenticity works against generating a coherent through line. It's of a piece with a film that feels garbled and shapeless throughout. There characters still have a vividness that is rare in the comic book genre, and that's due once again to dynamite casting. Downey is his usual charismatic and tortured self, Don Cheadle is a huge upgrade over Terence Howard, Sam Jackson's Nick Fury has an appropriately entertaining swagger, while Mickey Rourke and Sam Rockwell make the most out of their underwritten bad guy roles. The first Iron Man did a good job of mixing rock 'em sock 'em with effective character work. The sequel, like most blockbuster sequels, seeks to ratchet up every element from the first one that worked. When you're talking about CGI robots fighting, that's an easy enough task: just increase the numbers and firepower of said CGI robots. "More and bigger" is a strategy that just doesn't work when it comes to character and relationship arcs.