Iron Man 2 is a strange beast. When the hero of your movie spends his ass-kicking time underneath an expressionless metal mask, the civilian scenes have to do double duty. Interestingly enough, the large-scale armored ass-kickings turn out to be the least interesting parts of Jon Favreau's superhero sequel.
The original Iron Man film rode on the personal charisma of Robert Downey Jr. as inventor and playboy Tony Stark. For all of his efforts, Jeff Bridges couldn't make Obadiah Stane a compelling villain, and the climatic punch-up fell a little flat. But you didn't notice, because Downey inhabited Stark with such a cleverly-constructed persona, equal parts hubris and genius, that it was fun watching him slowly become a hero. The second film, without the charm of the origin story, needs to reach a little farther to keep momentum, and it does in sort of an interesting way: the arc reactor which saved Stark's life is killing him.
With his death looming large, Stark gets drunk, signs over his company and hands the armor over to the military, but a figure from the past (Mickey Rourke speaking intense Russian as Ivan Vanko, the villain known as Whiplash) opens the door to another plot of industrial espionage that - naturally - creates even bigger and badder armor for Shellhead to fight. But the film's best battle comes midway through, when Vanko ambushes Stark at the Monaco Grand Prix. With Tony out of his armor, it has a tension that the rest of the movie lacks. There's just so much that CGI punch-ups can accomplish, but luckily the scenes with Tony furiously working to find a solution to his palladium poisoning and his expanded relationship with Pepper Potts (and the introduction of the lovely Natasha Romanov, aka the Black Widow) kept me watching.