Flying is fun, but gameplay is extremely repetitive.
Story follows pretty closely the story of the movie, but since a videogame is a different medium comparing to a movie it's a shame that the story in the game doesn't really - how should I say it - happen. If you've seen the movie you know what's coming, but still you may have a hard time following events that take place on screen. Story is told through quite good cutscenes and excellent voice work.
Graphics are good in some parts while others are just plain ugly. Character models are excellent, but their facial animations are at times really weird. Environments are not detailed at all, but most of the time don't even notice it, since you're too busy flying above them. Sound design and music in general are well done and it helps a lot in creating a sci-fi feel and atmosphere.
Controls are good. It takes a while to learn them, but after that it's fun to fly around and shoot stuff. Game captures the most important aspect of a super hero game: you really feel like you're Iron Man and possessing nearly god-like powers along with your suit.
Gameplay is fast-paced third person action with a very repetitive mission structure. All you do is fly around and shoot stuff. That's it. You can create yourself some variety by grabbing jetplanes in mid-air or catch a missile, but these actions are hard to perform in a 3D space. There are some RPG elements in a way that you can upgrade your suit as you make progress. It's shallow, but at least they tried.
Aside from repetitive missions the save system is what can make your blood boil in rage: there are no checkpoints and usually that one mission consists of multiple tasks and can last up to 25 minutes. There are 13 missions in total and if you manage to get to the end it will not take you more than 5 or 6 hours.
If you are a fan of Iron Man I can say that there is some fun to be had in this game. Just make sure that you don't pay a full retail price for this below average third person action game.