Sometimes seeing the narcissistic playboy get superpowers as well as all the girls, money and fame can be very entertaining. It was certainly fun in the first Iron Man movie, in which Tony Stark partied it up in his stripper-pole-equipped private jet and later donned his superpowered suit to save the world from Obadiah Stane. Stark may be a cocky bastard, but he realized that his armor's unparalleled might comes with the obligation to use it responsibly.And so it's annoying to see Stark, played by Robert Downey, Jr., get into all sorts of trouble as both the Stark Industries CEO and Iron Man in Iron Man 2, as if he forgot any lessons he learned in the last film. As a sequel, I had hoped that Iron Man 2 would bring the billionaire industrialist closer to realizing what it means to be a superhero while tackling more difficult challenges than he had previously. What we end up with, though, is a mishmash of underdeveloped subplots which include a disappointing half-romance with assistant Pepper Potts (Gwyneth Paltrow); an involvement with the superhero agency S.H.I.E.L.D. that could confuse viewers who aren't fans of comic books and a conflict with the generic though admittedly badass villain Ivan Vanko (Mickey Rourke).

Despite his possession of the world's strongest financial and technological assets, there's a lot going against Tony Stark in Iron Man 2. His heart, for one, is failing due to contamination from the power core plugged into his chest. In an attempt to find an antidote for the rising toxicity in his blood, Stark looks to the company's history and encounters another problem: His father, former owner of Stark Industries, seems to have left him enigmatic clues regarding the Stark legacy. Things aren't going too well within the company, either, as Stark struggles with Potts in managing both the company and their relationship. And it doesn't help that the United States government is out to seize his power suit, attempting to claim it for military purposes. A rival weapons manufacturer, Justin Hammer (Sam Rockwell), is also out to get the Iron Man suit and eventually seeks help from the main villain of the film, reclusive Russian scientist Ivan Vanko. Vanko poses the largest threat to Stark, as the villain has built a formidable suit equipped with lightening-powered whips.

Amid these trials and tribulations, Stark still finds time to party and get drunk. After a particularly irritating scene in which he shows off his suit at a party, I began to wonder how, exactly, this behavior will pan out. An intervention from Nick Fury, played by an adequate Samuel L. Jackson, seems to be the answer to Stark's ego, but the subplot involving S.H.I.E.L.D. gets pushed to the side too quickly.

The issue is that there are too many conflicts in Iron Man 2, and none of them get adequately fleshed out. Ivan Vanko, particularly, lacks a satisfactory backstory, and we are left to understand him as the prototypical villain with all the expected traits: wants to kill a superhero, is a mad scientist, has an Eastern European accent and a grudge against the world, etc. It's a huge shame, considering the potential of both Vanko's original character and Mickey Rourke's exceptional ruggedness.

Another underplayed role is Scarlett Johansson's mysterious Black Widow. The combination of her mystifying sexuality and action-movie vigor makes for an impressive performance, but I'm left questioning her importance in the movie. Sure, as a member of Fury's clandestine organization, Black Widow contributes to foreshadowing the upcoming Avengers film (slated for a 2012 release), but in terms of the central plotline, we are left just as confused as Stark about who she is.

And while I'm nitpicking about roles: Don Cheadle was miscast as Iron Man's sidekick, James Rhodes. Director Jon Favreau might not have been directly involved in the replacement of Terrence Howard, who played Rhodes in the first film, but he should have realized that Cheadle is not exactly an action star. Cheadle's performance as Rhodes is so drastically different than Howard's that I considered the colonel in Iron Man 2 as an altogether separate character. A change in actors, whether the filmmaker's choice or not, creates an awkward disassociation from the first movie.

Since Iron Man 2 is first and foremost an action film, the most important question may merely be, "How is the action?" Though the battle sequences are less exciting than in Iron Man, they are nonetheless entertaining and help drive the plot forward. The special effects are impressive, but the flying sequences are hardly jaw-dropping compared to fare like Avatar. As far as action movies go, Iron Man 2 is by no means boring, but it lacks the depth of story and character development that I loved in the first film. Go if you are a fan of the comic book series, but the overstuffed plot and underdeveloped characters prevent this movie from being remembered as a satisfactory sequel.