People will tell you Iron Man 2 has too many villains, and that's why it's such a boring shambles. It's not true: Iron Man 2 only has one villain, and his name is Tony Stark. Spoilers ahead.
Iron Man was one of the best superhero movies of all time, because it had such a compelling story: Tony Stark is a cocky arms merchant, until he gets imprisoned by Afghan thugs, and discovers they're using his weapons. He gets a hole blown in his chest, and has to transform himself into an armored super-soldier to save himself and make right the wrongs he's done by selling weapons so promiscuously.
Released in the waning months of the Bush presidency, Iron Man uses Tony's journey to comment on the downside of American military power. Our might and arrogance can have unintended consequences, and our own heart may become wounded in the process — but we can make it right by taking responsibility. Superhero stories are always about the exercise of power, and America's role as the "world's only superpower" is always in the subtext of most superhero stories — but Iron Man found a new way to open up these ideas.
It's hard to imagine how you'd continue this metaphor in the Obama era, where the perception of America's foreign policy has changed a bit. But Jon Favreau and screenwriter Justin Theroux take a gutsy but disastrous decision — they make Iron Man the main bad guy in his own movie, and the whole long, meandering movie is about what's the matter with Tony.
In Iron Man 2, Robert Downey Jr. is playing Stephen Colbert playing Tony Stark. Where he was a cool jerk in the first movie, this time around he's a loud jackass. And without giving too much away, every bad event in this movie happens because Tony Stark is a jackass.
This seems to be a conscious decision on the film-makers' part. If you take a drink every time Gwyneth Paltrow, Don Cheadle or Samuel L. Jackson accuses Tony of being a douche, you'll need a bathroom break about half an hour into the movie — and you can go ahead and take a whiz, because you won't miss anything for about an hour.
To the extent that there are "villains" in Iron Man 2, Tony Stark creates them. Tony's decision to "come out" as Iron Man boosts his egomania to new levels, and he spends all his time showing off. He keeps humiliating Sam Rockwell, who's the world's most inept weapons merchant, until Rockwell's willing to do anything to show Tony up. (Really — the movie seems to suggest that Rockwell is a harmless loser whose weapons don't even work, until Tony gets under his skin.) Meanwhile, the movie carefully shows us that Tony's boasting and preening as Iron Man are what drive Ivan Vanko (Mickey Rourke) to go on a laser-whipping killing spree. Oh, and Tony claims he doesn't want to share his Iron Man technology with the military. Until he does, causing lots of civilian deaths.
(Oh, and I hereby apologize for making fun of Rourke's affectations, such as insisting that his character needs to have a pet cockatoo. Rourke is by far the best thing in this movie, and the only problem is that he's not on screen that much.)
In a nutshell, Stark paints a giant bullseye on his own chest and then struts around in public making a lot of noise. Any collateral damage, in that situation, is Stark's fault.
The "superhero creates his own supervillains" thing is a cliche — it's in The Dark Knight, and a lot of other places besides. When you're exploring the potential complications that can come from wielding lots of power, it's an obvious place to go. When a "good guy" is too powerful, more powerful "bad guys" spring up to fight him, and innocent people suffer as a result.
But then we get back to the fact that Iron Man, in this movie at least, isn't a good guy. I mean, we're told that he's "privatized world peace" and fixed "East-West relations," whatever that means, but those are a couple of throwaway bits of exposition. On the screen, where it matters, Iron Man does nothing good. The only good decision Tony Stark makes in the entire movie is making Pepper Potts (Paltrow) CEO of Stark Enterprises. The rest of the time, he's a strutting idiot. (The Dark Knight is very careful to show why Batman's existence is a good thing, even if he does possibly create the Joker. Iron Man 2 takes no such pains.)
Once again, Tony Stark's wounded body becomes the metaphor for the movie's progression. The reactor that keeps Tony's heart beating is giving him blood poisoning, and we see black lines spreading out along his chest, as his blood gets more and more toxic. And Tony's impending death drives him to become more and more obnoxious. And when Tony finally solves the "black squiggly lines of death" problem, it's by re-embracing his father, who started the family weapons business and represents everything Tony used to hate about himself. (It also involves creating a "new element," in one of the silliest scenes of pseudo-science of the past year.)
So like I said, Iron Man was so great because it was about Tony taking responsibility for how he uses his power. Just like Spider-Man. In Iron Man 2, Tony still wants to be in control over the power he wields, and avoid sharing it with others — but the movie makes it look as though this is purely to satisfy Tony's ego and control-freak tendencies. This time, power really is an end in itself.
What do you call a superhero who believes that power is an end in itself? Oh yeah. A supervillain.
The only time the movie becomes altruistic, in fact, is when it harkens back to 1974, when Tony's dad put together the Stark Expo. Back then, people still believed that technology would make the world a better place, and we had a bright future, blah blah blah. The implication seems to be that optimism and belief in the future are things of the past, and nobody can feel good about technology in our modern era. Tony makes a stab at bringing this spirit back, but Gwyneth insists that this is just about Tony's ego, which seems about right.
So bottom line — this movie is sort of the reverse of the original Iron Man, which showed Tony Stark transforming from a selfish asshole into a responsible adult. In this film, he transforms back into a selfish asshole, thanks in part to another traumatic near-death chest suck. This movie could be a challenging portrait of a hard-to-love anti-hero, except that it's incoherent and boring. (Seriously — people are saying this movie isn't as bad as Spider-Man 3, but I wasn't looking at my watch during Spider-Man 3. On the other hand, NPR loved this movie. So, you know, your mileage may vary.)
In the end, Iron Man 2 is a lot like Tony Stark himself: way too impressed with itself, and not really interested in whether you're having a good time or not.