At the end of Monday's preview screening of "Iron Man 3," a woman chastised a man right back into his seat.

"You can't leave yet," she told the stranger. "Marvel movies always have something after the credits." He paused, then dutifully sat back down.

She was right, of course. There is indeed an amusing bit at the end of a very long credit roll. Without spoiling the joke, we can say that it speaks to the pleasures but also the failings of this latest installment of the Tony Stark/Robert Downey Jr. show, which finds the superhero wrestling with his narcissism but Hollywood willfully avoiding its own need for a little behavior modification.

When last we saw the buff billionaire geek and his metallurgic alter ego, he was hanging out in New York City with the Avengers. As this story gets underway, he hasn't really made peace with all he learned about himself during that exquisitely heroic battle royal.

So in his massive digs looking out over the Malibu seaside, he tinkers, stays awake hours on end, worries his robot Jarvis (voiced by Paul Bettany) and tries not to worry live-in love Pepper Potts (Gwy-neth Paltrow).

Potts heads Stark Industries, and Happy (Jon Favreau) is now the bullish — as in "in-a-china-shop" — head of security for his friend's vast corporation. Don Cheadle returns as Col. James "Rhodey" Rhodes, whose superhero persona War Machine has been rebranded "Iron Patriot" by the government.

Downey is as nimble and wisecracking as ever. When Stark meets and enlists the help of an 8-year-old tinkerer named Harley (Ty Simpkins) after disaster has struck, his banter is fleet, funny and a bit inappropriate.

The actor wears this character like a second skin, one in need of shedding perhaps. And director Shane Black and Drew Pearce's script has Stark reckoning not only with past heroics but also with past hubris.

The story flashes back to a 1999 New Year's Eve party where Stark plays typically fast and loose with a genetic researcher he beds, Dr. Maya Hansen (Rebecca Hall), and is even more dismissive of a hobbled, enthusiastic bio-entrepreneur named Aldrich Killian (Guy Pearce) who wants to pitch Hansen an idea. Those slights will come back to haunt him — and the nation.

"Iron Man 3" is in part a story about karmic comeuppance, about Tony Stark's easy arrogance finally catching up with him.

That's not the problem. It is also about terrorism, which is.

Things are set in motion with a deadly explosion outside the former Grauman's Chinese Theatre on Hollywood Boulevard. Happy is injured, which brings Iron Man into the picture.

This set-up seems to combine the worst of actual recent events with the sorrow of last year's shootings at an Aurora movie theater.

Ben Kingsley is disquieting as a figure calling himself The Mandarin (an update of the comic book's fiend). He hijacks broadcasts to issue warnings and televise acts of violence. He has a long beard and wears his hair in a top knot. His shtick is all over the place. He definitely conjures the ghost of Osama bin Laden. He swings his ideological ax wildly. In one of his videotaped free associations he even mentions Colorado's Sand Creek Massacre.

Injured U.S. soldiers suffering limb loss and post-traumatic stress disorder also figure uncomfortably into the plot line. Killian — once disabled, now vigorous — is using a genetically altered virus called Extremis to weaponize former soldiers.

Iron Man 3" feels like an exploitative mulching of present-day anxieties. The script is ambitious but not wise enough to be rightfully cathartic. It's more Cuisinart than art.

Still, "Iron Man 3" is not without humor, and Tony and Pepper's relationship has charm. The movie also has a twist that is unexpected, hilarious — and strange enough that it suggests Black and Pearce were actually trying to insert kernels of wisdom in their big-popcorn flick.

Only it happens too late into a PG-13 movie that allows too much mayhem when something more heroic is required.

Tony Stark is growing up. But a similar transformation from the studios isn't so apparent.

Lisa Kennedy: 303-954-1567, lkennedy@denverpost.com or twitter.com/bylisakennedy

"IRON MAN 3." Directed by Shane Black. Written by Drew Pearce and Black. Photography by John Toll. Starring Robert Downey Jr., Gwyneth Paltrow, Don Cheadle, Guy Pearce, Rebecca Hall and Ben Kingsley. Rated PG-13. 130 minutes. At area theaters in 2D and 3D.