Flashy and frivolous, an exhibitionist who likes the glare of public attention, he's a light knight with a thick skin.

Traditionally, protagonists are punished for their hubris, and the first "Iron Man" movie went through those motions. But Downey enjoys Stark's arrogance too much to eat humble pie. He's always resisted the idea of playing the repentant. Stark may have developed a conscience after his run-in with the Taliban in the first movie, and even turned monogamous for Pepper (Gwyneth Paltrow), but he's still a flip, cynical hedonist at heart.

So what are we to make of the anxiety attacks that cripple Mr. Stark in Shane Black's "Iron Man 3"? Apparently he's freaked out after his mind-blowing experiences with "The Avengers" last summer (though no one else seems concerned that Norse gods are at large in the cosmos, and when the going gets tough you do wonder why he doesn't pick up the phone and ask his new buddies for help -- not the only plot hole by any means).

Black, who wrote "Lethal Weapon" way back when and more recently helped restore Downey's career with "Kiss Kiss Bang Bang," may have hoped that a sliver of self-doubt would crack open Iron Man's emotional armor and restore the human face behind the mask, but Downey shows no interest in introspection.

Black systematically strips Tony of almost everything he has -- gadgets, gizmos, his strongest suit -- but the actor merely shrugs it off. There's a lot of faulty wiring this time round, technology that seems as flawed as its inventor, but if his problems are largely of his own making Tony remains supremely unfazed, always primed with a quip and a smirk. Downey may as well be playing "Irony Man."

Stark's arrogance and narcissism come back to haunt him in the form of spurned entrepreneur Aldrich Killian (Guy Pearce) and a larger-than-life terror-monger by the name of "The Mandarin" (Ben Kingsley).

A cross between Osama bin Laden and Fu Manchu -- but with the rumbling, tumbling vocal stylings of a Southern Baptist evangelist, The Mandarin brings out the best in Kingsley, who hasn't had a role as juicy as this one for donkey's years. Mandarin is a worthy nemesis, an extravagant showman like Tony who can hack into broadcast feeds at will, and claims credit for a string of bombings across the U.S. When Hap (Jon Favreau) is caught in one blast, Tony takes it as a personal affront -- and impetuously calls fire down on his own head.

There's an off-the-cuff quality to the storytelling here -- the movie rewrites its own laws of physics whenever it's convenient to do so -- which by rights should be a bigger problem than it is. But Black and/or co-writer Drew Pearce know how to write snappy dialogue. Even if they don't mean a thing, their scenes have plenty of zing. They also have an ace up their sleeve, a trump card that puts a giddy spin on the third act at just that point where both the previous movies began to run out of stream.

To say more would be to spoil the fun. "Iron Man 3" has plenty to offer on that score. It's a confidently tongue-in-cheek piece of blockbuster engineering, sweetly calibrated to Downey's cavalier appeal and to Kingsley's oddball interjections, a battle royale of rampant egos in which acting speaks louder than words.