Iron Man ramps up the camp but falls flat 

If Iron Man was an embodiment of the United States' single-minded crusade to impose a Pax Americana at the point of a spear, then the Tony Stark in Iron Man 2 is most aptly viewed as a metaphor of his own. The bajillionaire protector we meet in the sequel has fully assumed the qualities of the proverbial Ugly American, exuding the arrogance and entitlement of Uncle Sam as the world's unaccountable enforcer.

Here, Stark dons sunglasses and blows dismissive kisses at a Congressional committee bent on bullying him into relinquishing his ferrous-plated super suit. "I am Iron Man; Iron Man is me," he declares to the Senate subcommittee. It may as well be Robert Downey Jr. making that claim, for while multiple actors have capably portrayed Superman and Batman on the screen over the years, it is nearly impossible to imagine anyone other than Downey in this role.

Congress is questioning Stark out of concern for the country's increasing dependence on him; not coincidentally, the politicos are also sniffing around for ways to exploit him before external enemies do. These are provocative issues, even if the notion of escalation in the face of an omnipotent superhero was explored to much greater effect in Christopher Nolan's Batman films. Problem is, they are all brought to bear inside the first 15 minutes of Iron Man 2. The remainder of its clunky, two-hour-plus running time is spent sidewinding through a series of bullets, bombs, babes and disjointed plot points.

Escalation begins before the opening credits in the form of tattooed, vodka-swilling Ivan Vanko (Mickey Rourke), who speaks in three-word sentences and whose unexplained rage against the Stark family leads him to construct a plasmatic lash he intends to lay to Iron Man. Rourke's two battle scenes bookend a performance that mostly features him furiously tapping on computer keyboards. More significantly, he is one of two barely realized baddies whose narrative impotence emphasizes Iron Man 2's violation of rule No. 1 for successful action films: the presence of a compelling villain.

Vanko's partner in evil is Justin Hammer (Sam Rockwell), a rival weapons contractor with aims on developing and outfitting the military with its own high-tech wardrobe. Rockwell, normally a durable actor, misplays Hammer with an exaggerated cartoonish affect that wears out its welcome after two scenes. Add to that mix Stark's encroaching mortality, daddy issues and Stark's increasingly erratic behavior and heavy drinking that prompts his military buddy, Rhodes (Dan Cheadle, replacing Terrence Howard without the audience batting an eye), to commandeer one of Iron Man's suits. Oh, and don't forget Scarlett Johansson's role as shapely Natasha, Stark's newest personal assistant and acrobatic woman of mystery. Still, the series' backbone remains Downey's wiseacre high wire act, particularly his banter with his girl Friday, Pepper Potts (a fine Gwyneth Paltrow).

The worst moment in Iron Man 2 finds a drunken, costumed Stark rampaging through his own birthday party. It's a scene worthy of a bad comic book-movie parody, and it underscores the film's fundamental problem—its excessive jokiness. The first Iron Man's levity rested with Downey's bravura performance and director Jon Favreau's fanboy sensibilities. What's different this time out is the screenwriting is handled by seemingly kindred spirit Justin Theroux (Tropic Thunder) rather than Mark Fergus and Hawk Ostby (best known for Children of Men), a decision that may have enabled the sequel's flaws. The original film was a popcorn movie that dared to succeed during an era of brooding movie heroism. Its sequel suffers not only by comparison but also due to its strained efforts to please an audience now hip to its hipness.