I want to just say upfront that I'll be ending the review on a high note, so the stuff I liked will come last.
There was a lot of anticipation for this one, as there should have been. How could there not be? Iron Man helped changed the world's ideas of how comic book adaptations could be done right. Like many sequels though, this one tries to do a lot (too much perhaps), and as a result, fails to quite match or surpass its predecessor.
After having outed himself as Iron Man, Tony Stark must deal with the repercussions, namely in the form of business rival Justin Hammer, and a vengeful psychopath named Ivan Vanko/Whiplash. There's also some more build up in the Marvel Cinematic Universe, sowing more seeds for The Avengers and other related films.
I like that they tried to build on the story, but given the film's runtime, they should have made the film longer. It needed it, and for two reasons: action scenes and characters. They added a handful of new characters, and, while they aren't cardboard cutouts, they could have used a lot more fleshing out. As for the action: there's not enough. One action set piece per act is a let down, especially since the action closes out each act. Like the first film, this one has a good amount of humor. However, I think there was a bit too much of it, and it really hurt the tone. The blending of drama and comedy didn't gel real well here, resulting in scenes that were lighter than they needed to be, or lighter when they didn't need to be, ie the Monaco attack scene: there's some slapstickish moments when there needed to be fear. It stuck out and took off a little too much edge.
Back to characters: besides all needing to be fleshed out more, I didn't like how they handled Justin Hammer. He's too goofy and over the top...and annoying. Rockwell does a good job, don't get me wrong, I just thought he could have talked less and not been such a tool. They also could have used Whiplash a lot more. Another thing I didn't like was how the darker elements with Stark's situation played out. I'm happy they had him drinking more and raised the stakes with his health, but the plot points with his situation and Pepper needed to happen earlier.
Look, I didn't hate this movie. I actually rather enjoyed it. It was decently made, had great effects, was very entertaining ,and had ambition. It just tried to do too much given the run time. The performances were pretty good, the casting was likewise good, and it was never boring. A lot of my issues with it are nitpicks, so that's why my grade isn't lower. The issues are still something that can't be ignored though. Besides being made longer, I think a few more re-writes with the script would have been great as well.
I can be forgiving because sequels are tricky, but I really hope that future Iron Man films avoid the missteps that this one had. I like to laugh, but they should darken the tone and tone down on the jokes. Also, with the plot, they either need to just pick one or two things to focus on, or push up the run time but then execute it in a way which doesn't feel too bloated or forced. And of course, more action. It's not impossible to throw in tons of story and character yet still have plenty of action as well and make it all work. I didn't want to have to do this, but just use Spider-Man 2 and The Dark Knight as examples.