WASHINGTON (Map, News) - An Ironman triathlon race involves a 2.4-mile swim, followed by a 112-mile bike ride and a marathon run of 26.2 miles. Marvel’s action-packed “Iron Man,” based on Stan Lee’s second-tier comic book superhero series, isn’t quite as exhausting.

Nevertheless, for the most part, it does indeed rock. 

The target audience of hard-core fanboys will no doubt be thrilled about this long-awaited big-screen adaptation. Its sexy, eventually unrelenting high-tech violence blings it up 22nd-century-style, with visuals somewhere past the place where “Robocop” meets “Transformers.” And yet more sophisticated audience members get their pleasures too, insofar as a predictable popcorn movie can deliver them, especially in the more character-focused first half.

That’s because the knowing and entirely convincing Robert Downey Jr. infuses Iron Man, aka Tony Stark, with his own fascinating personal and actorly essence. Director Jon Favreau and the script (credited to four different writers) give Downey plenty of free rein. So his quirky wit and world-weary depth have the chance to elevate what ultimately must become the usual silly cartoon fantasy about a paranormally souped-up crime fighter demolishing megalomaniacal baddies.  

Compared to the best of the most recent superhero extravaganzas, Marvel Comics’ first self-financed production from its own movie studio doesn’t quite achieve the graceful imagery of the first two “Spider-Man” installments or the affecting darkness of “Batman Begins.”

But the story line of “Iron Man” does resonate with contemporary relevance.

The first act of the film unfolds largely in the theater of terrorist tyranny and American military occupation in Afghanistan. And by its last act, the film has delivered a condemnation of the military-industrial complex and factional aggression. 

The mild-mannered Stark starts out a billionaire playboy war profiteer, a genius inventor behind a weapons manufacturing empire. But after he is kidnapped by terrorists and gets a firsthand look at what his own products have wrought, Stark has an epiphany. Of course, he — like all of his fellow superheroes — must concoct for himself a hot-looking, specially-endowed fighting costume that will give him the capabilities to kill the killers.

The supporting players are all serviceable in their roles, with Terrence Howard as Stark’s trusty Pentagon liaison, Gwyneth Paltrow as his Miss Moneypenny — here named Pepper Potts — and a bald Jeff Bridges as his suspicious business partner Obadiah Stane. But it’s Downey who really puts the mettle in this “Iron Man.”

‘Iron Man’

Four Stars