Iron Man 2 is a perfectly efficient blockbuster, but not a perfect film. In the era of Dark Knights and Bourne Ultimatums, it might be more common for fans to expect a sequel to live up to – or, rather, even surpass -- its predecessor, but let's be frank: most of them don't. Whether it's Rocky or Police Academy, most sequels tend to bury themselves into the ground.

Held to this standard, Iron Man 2 is entirely competent – a fun, mindless blockbuster – but it's not necessarily superior to the first film, and that might disappoint fans who were expecting more.

It's probably better to address the weaknesses first: number one would be Mickey Rourke's role as Ivan "Whiplash" Vanko. When Robert Downey, Jr. campaigned for Rourke to be cast during the 2009 Oscar race, I was ecstatic; I thought he'd knock his role out of the park. And he definitely tries his best, but the character – as written in Justin Theorux's screenplay – is curiously minor (and, truth be told, his suit's pretty lame). He has a grand introduction during the pre-credits; then disappears for most of the film. He reappears at the end for what we expect to be a climactic battle, but (without spoiling anything), it's even more underwhelming than Jeff Bridges' battle at the end of the first film, which was one of the few things that some fans seemed to quibble about back then.

Some critics have written off Iron Man 2 as being another Spider-Man 3 due to its extraneous subplots and characters, but honestly, it's not nearly that bad. Yet there's no denying it does feature too many characters – Black Widow (Scarlett Johansson) serves no true purpose other than to establish herself for further Avengers-style spin-offs; Samuel L. Jackson's Nick Fury seems to appear merely because of his purpose in the grand scheme of things rather than because he's necessary for this particular film's narrative. And director Jon Favreau's Happy Hogan character (who showed up briefly in the first film) has waaay too many "cameos" here – maybe he's setting himself up for future installments (which would assure him a spot in the films he's not directing, I suppose), but the character feels wholly pointless. And Pepper Potts (Gwyneth Paltrow) is largely relegated to the sidelines – if you took her out of the film you probably wouldn't really notice.

Sam Rockwell rocks (I'm surprised Peter Travers didn't try that one in his review) and is one of the strengths of the film; charismatic and funny, he gives Downey, Jr. a run for his money. He was one of the studio's original choices to play Tony Stark during pre-production on the first film, and after seeing him here, as an equally egoistic adversary to Stark, it's easy to see why.

Downey, Jr. himself is still great, but – much like his real-life self – much of the sudden public adoration has rendered him even more arrogant, and I have to admit that, as a result, I didn't enjoy his role quite as much. It's not so much the performance (Downey's rarely in poor form) as it is the character.

These are the negatives. The film does have a lot going for it – it's pretty fun, goes by rather quickly (despite all the subplots going on) and features enough well-edited action to please the sort of junkies who loathed Transformers 2. (Plus, none of the robots in this one talk jive.) While not quite as impressive as its predecessor, Iron Man 2 is definitely an efficient blockbuster. There's nothing here as complex or challenging as, say, The Dark Knight, but it is what it is, and in spite of some wandering plot lines, it doesn't attempt to overreach. You pretty much know what you're getting going into this flick, which is more than can be said for many pictures.