After Christoper Nolan's Batman movies (Batmen?), Iron Man is the best superhero franchise there is. The first two X-Men were great, but Brett Ratner shit out the third one, to everyone's surprise, and Raimi did the same with the third Spiderman, which wasn't entirely his fault. Except for the jazz scene. That one was him.
Iron Man 2 is definitely a sequel though. Obviously, there's that number at the end of the title, but it does sequels do: make things darker. I blame it on Empire Strikes Back, but I guess it makes sense if you take the whole trilogy as one story. The first movie sets everything up, the second puts the characters through a bunch of challenges, and the third is their redemption. I know Iron Man isn't supposed to be a trilogy, but I would not be surprised to see a third one after the Avengers movie is out. More on that in a bit.
When I say that Iron Man 2 is darker, I don't mean Nolan dark (man it's hard not to draw comparisons to Batman). Since this is a new movie, I won't go into detail, but I will say things don't always go Tony Stark's way. There are still some very funny parts, but Stark definitely has a lot more to deal with, and some of it he doesn't handle as smoothly as he did in the last installment. I will say that Whiplash was a really lame villain. I'm not even sure he was supposed to be the main bad guy, maybe it was Sam Rockwell, who was super awesome as Justin Hammer.
Back to the Avengers stuff. Samuel L. Jackson appears before the end credits this time, and there's a lot more S.H.I.E.L.D. stuff going on. Maybe my favorite part of the movie was the sense of shifting the story did from Tony Stark as just Iron Man to Tony Stark and his role as an Avenger. There was a lot more big picture stuff going on, and as a result, I cannot wait for the Thor and Avengers movies.