There’s nothing outwardly wrong with Tony Stark, and that might surprise some people; no sticky substance oozes from under his skin, no nightmares of murdered parents haunt his sleep, no mutant powers are his to toy with. What sets the guy apart isn’t a superpower, or even a super dysfunction, but a supersized intellect that he has learned to suppress through the years in order to make a quick buck. He’s a curious, conflicted fellow.

So is the updated version of his story, Jon Favreau’s “Iron Man,” which lands in theaters on Friday. Unlike so many other recent superhero blockbusters, which have arrived with more interesting gadgets and special effects than human beings, the new “Iron Man” rarely lingers on computer-graphic fights and flourishes any more than necessary. It has been reported that Mr. Favreau relied heavily on an actual iron suit in many sequences, to make the film feel as real as possible — or, at least, to make the guy inside it seem as human as possible.

At every turn, “Iron Man” makes unexpected choices (except, perhaps, during the end credits, where Black Sabbath brings things home). Why does that suit look so real? Because more often than not, it is. Why does Stark seem to have more personality than your standard superhero alter ego? Because he’s being played by Robert Downey Jr., an actor who couldn’t be boring if he tried, finally getting his chance to drive a summer blockbuster. Why does the film’s sense of danger feel so real? Because as Stark is ambushed, held hostage, and lightly tortured in modern-day Afghanistan, the story hits a little close to home.

Even the movie’s climactic battle is less about a surge of special effects than about one scientist challenging another scientist to a duel of inventions. It’s safe to assume, however, that most audiences have never seen a scientist this suave. Strutting his stuff between the limo and the lab, Stark is a man with the world in his hands. From his cool shades to his private jet, his parade of beautiful blondes to his cliffside Malibu mansion, Stark is the toast of his industry, regularly gracing magazine covers.

He’s a weapons manufacturer in modern-day America — which means that business is good. When Stark flies out to Afghanistan to present military officers with his latest weapon, which can obliterate the enemy with greater efficiency, he doesn’t so much pitch the officers as let them in on the future; please make the check out to “Cash.”

But after an ambush attack kills American servicemen and almost kills Stark, he finds himself sitting in a cave with rifles aimed at his head, ordered to build weapons for the enemy. Realizing he has been attacked with one of his own weapons, and aware that the shrapnel in his chest is designed to destroy his vital organs, he must build an implantable device to stave off death.

The implant gives Stark the idea to build a suit made of iron that will help him escape back to America. But he is a changed man when he returns, and it doesn’t take long for the people in his life to grow concerned. His assistant, Pepper Potts (an underused, charming-as-always Gwyneth Paltrow), is worried when Stark starts spending all day in the lab, turning down the red-carpet invites he so cherishes. And his business partner, Obadiah Stane (a devilishly bald Jeff Bridges), doesn’t do well trying to contain his outrage when Stark announces that his company will immediately shutter its weapons division.

You don’t have to be a mad scientist to figure out that Obadiah will channel his rage into super-villainry. But when the two metal monstrosities finally meet, the film’s deeper theme of the moral versus amoral uses for science bubbles to the surface, even if the story is considerably less inclined to the Cold War-style patriotism that propelled the original comic-book hero created by Stan Lee and Larry Lieber in 1963.

There’s chunkiness in the third act of “Iron Man,” and some of the characters are underwritten in Paramount’s bid to make that all-important 126-minute mark (no doubt some executives would have preferred 90 minutes). But even in its closing moments, there’s something fascinating about the way Mr. Favreau takes a few steps back from the likes of “Transformers,” “Fantastic Four,” and “X-Men: The Last Stand.” The world of Tony Stark is not one steeped in far-fetched fantasy, but in the dirt and sweat of hard labor. Iron Man is not a hero because of his gadgets, nor his intellect, but because of his work ethic.

ssnyder@nysun.com