I'm not going to refrain from spoilers here because...who really gives a shit? If you are into Iron Man and stuff, don't read it. I neither liked it or hated it. I knew what I was getting into. Here are some observations:
Iron Man 3 is really loud.
Robert Downey calls a 10 year old orphan a pussy, which was cool.
The blond who plays his girlfriend is a really dull actress. The movie shows off her abs toward the end, but I think that's CGI because she's such a bean-pole. Everybody has to have abs in these flicks though.
I hope they shoved a few million dollars up Ben Kingsley's ass for being in this. You figure that guy has better things to do, but maybe he has a drug addiction to feed, so... He and Robert Downey are the best things about the movie.
Robert Downey's character has "post traumatic stress" syndrome in the movie, which makes him wuss out a lot. I guess they wanted to add some kind of bullshit drama to a movie in which people really only want to see explosions and PG-13 violence. This adds an unnecessary 30 minutes to the running time.
The villains are people who undergo some kind of weird DNA thing that turns them into fire monster people. As the movie goes along, it gives them increasing superhuman qualities because otherwise Iron Man could easily just rip their fucking heads off and there wouldn't be much of a challenge for him. I think people would have liked to watch him rip some heads off. Since they're fire monster people, the film makers could easily PG-13ify the onscreen manual decapitations. These guys are just arbitrarily superhuman--whatever the screenplay needs to provide a challenge to Iron Man, they give to these assholes. At one point, Guy Pearce shoots fire out of his mouth and I thought, "oh, so they can do that now too, huh? Gosh." Guy Pearce is the villain, by the way. SPOILER He is a forgettable villain.
At the end Robert Downey tells the blond that he's not going to be the Iron Man anymore, and in fact blows up all his Iron Man suits, erasing any chance of more sequels, to demonstrate that he's going to dedicate himself to their relationship. Relationships, after all, are what superhero movies are about.