Surviving his own private Afghanistan hostage drama, billionaire industrialist Tony Stark returns home, as he terms it, "conflicted." You could say the same about "Iron Man," in which a war profiteer develops a conscience, an off-and-on politicized streak as well as a titanium alloy flying suit, with jets of flame shooting out of his palms.

As big-budget comic book adaptations go, this one's a gratifying freak—the right kind of conflicted, as well as quick-witted. It's a lot of fun. The style may be in the performances more than in the film itself, directed by Jon Favreau ("Elf," "Zathura: A Space Adventure"). But Favreau's picture, rumored to have cost $180 million, doesn't look, feel or play like a heavy-spirited blockbuster.

Mainly it has Robert Downey Jr. The newly insurable actor, who has had his run-ins with various chemicals in the past, plays this louche playboy with a knowing glint in his eye. You swear you can see that glint even when Stark's head is stuck inside the red-and-gold helmet with the slits for peepholes. And when he bandies the badinage about with Gwyneth Paltrow, who plays Stark's gal Friday, Virginia "Pepper" Potts, you're seeing two actors who understand each other completely, who can mine the pulp fictions at hand for both earnestness and laughs. Has there ever been a comic book movie with such high-comic fizz in the dialogue scenes?

The Iron Man created in 1963 by Stan Lee and company had some interesting wrinkles: He was a hard-living hedonist (and years later, an alcoholic) who, as originally drawn, looked like a mustachioed Efrem Zimbalist Jr., or a variation on Clark Gable. Downey evokes a different sort of glamor, that of a famously self-destructive hipster fending off middle age as best he can. In the comic book original Stark fell afoul of a Ho Chi Minh-styled dictator, returning to safety with shrapnel dangerously near his heart and a cylindrical metal canister planted in his chest. (It's electromagnetic, or non-returnable, or something.) The Vietnam era Iron Man's mission was simple: destroy communism, one North Vietnamese at a time.

Times change, wars curdle and film producers must arrange for a new villain. Behold: the Taliban, finally good for something. In the film's prologue Stark and his Air Force pal Rhodey (Terrence Howard in a functional role) meet in Afghanistan for a demonstration of Stark Industries' latest and most fearsome arms. Then comes an ambush, and Stark is captured by cave-dwelling insurgents and forced to create for them a horrible new weapon of mass destruction. Instead, with the help of a fellow prisoner (Shaun Toub), he creates a crude prototype of Iron Man and blasts his way to freedom.

Back in America with the magnetic chest canister keeping him alive, Stark has other battles, including a struggle for the future of Stark Industries waged with a steely colleague played by Jeff Bridges. It's a kick to see Bridges munching on an adversarial role such as this. Regarding the climactic metal-on-metal smackdown, well, no one (not even 14-year-old boys) will consider it the film's highlight. It doesn't impart a "Transformers" headache. But we've seen it before. Favreau is a solid director; what's missing is a sense of distinction and eccentricity in the big action sequences to augment his facility with actors. (He saves himself a bit role as Stark's chauffeur.)

The best scenes keep Stark front and center and riffing on the reluctant-superhero premise. In the sleek, well-appointed garage of his fab Pacific coast mansion, Stark noodles with his new, improved Iron Man gear. Once he's airborne Iron Man recalls the jet-pack days of "The Rocketeer" (a tasty film, though a big flop). What "The Rocketeer" lacked in star power, "Iron Man" has in spades. When Stark mutters lines of self-realization such as "I could ... actually do some good," Downey finds just the right spin. He's like Tobey Maguire in the first two "Spider-Man" pictures: an unlikely casting choice, but the only correct one in retrospect.

See the trailer and find local showtimes for "Iron Man."