Why anyone bothers making a smart superhero movie is an interesting question. The many millions who troop dutifully to see Spider-man or Transformers know what they want, and get it, and it has little to do with smart movie-making. International audiences, who get a big say, don’t want or need clever scripts.

The new Iron Man fetishes the original Marvel comics in a precise and, to my memory, unique way. The Spider-man movies, with their unrelieved freneticism and crayon-drawn scripts, bludgeon audiences with their plots; Alfred Molina stands in a chamber and gets eight steel arms welded to his torso and onlookers barely find it unusual.

In Iron Man, most of the movie is devoted to explaining the process by which our hero, played by Robert Downey Jr., creates his steely persona. It is a formula (Spidey had to learn to web-sling, too), but within that context the movie’s deep interest in this process bespeaks a love of the subject and a respect for audiences generally absent in the typical super-hero foolishness.

Jon Favreau, who directed, steps up dazzlingly in a massive undertaking whose technical trappings are both nuanced and assured. The Swingers writer and star-turned-director, whose weight had ballooned along with his filmography (most recently Elf), has a small role here, showing off a svelter physique. He refuses to make Iron Man frenetic and made sure it was written by adults—smart and funny ones—who understand story arcs and understand their lead actor. Again, it’s all formula, right down to the Iron Man-on-Iron Man climax, but it is so handsomely done, so lovingly and amusingly presented, that that you fall into the same mindset, and wind up enjoying yourself immensely.

Bestriding the film is a satisfying and mischievous performance by Robert Downey Jr., whose ragged psyche and roguish countenance illuminate the character every which way but loose, and that too, come to think of it. The very idea of Tobey McGuire as Spider-Man is preposterous; where Superman’s Clark Kent persona was a masterpiece of misdirection, McGuire’s Peter Parker has simply no sign of a superhero’s soul, and neither the actor nor the director, Sam Raimi, try to give him one. Downey, by contrast, has the natural arrogance of the breed and the monomaniacal glare as well; and Iron Man’s methodical pace gives him the time to re-create himself persuasively, making the film’s last line reverberate.

The supporting cast—Jeff Bridges, Gwyneth Paltrow and Terrence Howard, in descending order of how much they are given to do—is so high-level none manages to get steamrolled by Downey, who plainly has something to prove and is, delightedly, given a script packed with self-referential lines. (“I should be dead right now” etc. etc. etc.) Again, as the makers of The Hulk found, a few years back, there’s not a huge upside in making a superhero movie for adults; I don’t know why the Fav & Co. did, but the result is a lot of fun.