Iron Man 2 is the rare sequel that doesn't surpass the original. It's no Dark Knight, Spider-Man 2, or X-Men 2.
It's not a bad movie mind you. I found the cast to be by and large very good. I loved Rhodie's storyline. Don Cheadle is a much better actor than Terrance Howard and made a very convincing War Machine. Scarlett Johannsenn was beautiful and did a good job. Downey is Downey and he's very good. Good supporting turns by Samuel L. Jackson, Jon Favarau, and Garry Shandling as well. The O'Reilly Factor bit was clever. Liked the first fight with Whiplash. Terrific FX once again. And hey, love the Marvel connections throughout this film.
But it has a number of factor going against it. The narrative structure isn't very strong. If people didn't think there was enough action in the first one, there isn't exactly a lot in the second one. The final battle scene is anti-climatic and very short. We rarely see Tony as Iron Man. We hear about all the great things he does but see very little of it. The humor, which worked so well in the first film, is on completely overdrive here and a lot of this film comes off as overly silly. Downey's funny but the Stark character he plays (really, he's just playing himself) is ratcheted up by about 100% and it's excessive.
Perhaps the biggest flaw is this film has a very, very weak presence in terms of villains. Mickey Rourke's character says little and does little. After being convincingly defeated by Stark early in the film, he just lurks in the background until the end where he is again convincingly beaten by Iron Man and War Machine. I'm a fan of Sam Rockwell but I found his character to be largely annoying. There's no sense of menace in either of these characters and as a result, they feel like they're not a threat at all.
Rourke's character for instance is supposed to represent what Tony Stark could have become. But the connection is very weak and not all all developed.
It's an enjoyable flick but I feel like the producers decided not to try too hard when they did this film.