Story: Although it started out rather abruptly, the story was not confusing. I never got lost.
Main Character: Tony Stark was ok, and I liked him better in this movie for some things, but his trademark scathing wit is really nowhere to be found.
Supporting Cast: Happy Hogan was fun to watch. Pepper was kind of in and out, but mostly in. I think Rhodes was best, though.
Music: More of the rock style that fits the Iron Man character, but there was no melody I could latch on to that I could be like "This is the IM theme, this is cool. I want this." Unlike typical movie music, it kind of faded into the background.
Humor: There was surprisingly little humor in this one. The most memorable humor played like ridiculously blatant product placement. There was a silly action sequence or two, but to describe them properly would be a spoiler, so I can't.
Plot Twists: I am not aware of any parts that were real surprises, except the one at the very end. That was cool. Otherwise, everything that happened got untwisted and processed as "Well duh that was going to happen."
Final Thoughts: Downey and Cheadle played great together. Their interactions were the highlight of the show. If you didn't really like IM before, this one will not make you say "I take it back, He's cool." It was a fun movie, but unlike the Avengers, not one I would be enthusiastic to sit through again. Lumping the whole movie together, I would score it as pushing 7.