If you liked Iron Man 1, avoid this film. This might be worth watching if you're about to watch Avengers.

Rating: 6/10 (9 May 2013)

Decent action scenes, a believable and interesting villain alongside one that you just want to hate. And what seems like half of the movie wasted on a worthless subplot that just makes you scratch your head at the stupidity of the characters involved. If you can watch this movie without thinking about any of it, it will turn out alright. It has numerous small bits that segue into the Avengers movie, but isn't really necessary to watch beforehand; still, while not a good movie on its own, could be worth watching as a marathon with the others.
**Spoilers Below** When Tony Stark woke up in Iron Man 1, an electromagnet was in his chest, attached to a car battery, with the somber note that, when the battery ran out, he would die; that he has a few days of life on that battery before the end.
In Iron Man 2, the entire movie plot is based around 2 elements; a relatively well executed revenge plot by one of Stark the Elder's old business partners that saves the movie; and the idea that the palladium- based reactor is toxic and slowly killing him, so he needs a new source.
The latter is the serious problem with the movie, and not just a huge waste of time, but also so interconnected with the other plots in the movie that it hurts them all. We already know he doesn't need the toxic reactor to survive, if we've seen the first movie. We already know that an old rusty car battery has enough juice to keep him alive for days.
Rather than just glossing over this non-issue with perhaps a brief cut-scene of him making a new reactor, or modifying some laptop battery tech and leaving his reactors in the suits, they instead go on a long, drawn-out "I'm dying and need to settle my affairs" tour, which gives a handful of decent comedy moments but otherwise just ruins what could otherwise have been an enjoyable movie. Even if they'd come up with a plausible reason for him to be dying, and then a plausible cure, this would still have damaged the movie; but not nearly as badly as simply throwing together the first piece of nonsense that came to mind.
Ignoring that, the final villain bears a close resemblance to the Iron Monger from the first movie, but is still done well and different enough to be interesting.
Overall; cut out many of the scenes of the movie before he completes his new toy reactor and it would be great. As-is? Strictly average, lifted slightly above by some good action scenes.