This may seem a strange assertion to make about an acclaimed actor who's been actively working in the business and has a fully deserved Oscar nomination to his credit, but I'll put it out there anyway. Playing brilliant, wealthy industrialist Tony Stark, the man who dons the armor to become the title superhero of Iron Man, Robert Downey, Jr. gives one of the best, most smartly focused performances I've ever seen from him. Downey has usually been most successful onscreen when he's been shrewdly cast: as the egotistical, womanizing actor in Two Girls and a Guy or as the burnout reporter enamored with his own blooming fame in David Fincher's Zodiac. In roles like these, Downey's fussiness as an actor becomes an asset. He's incapable or unwilling to let a small scene remain small, filling his performances with tics and business and restless mannerisms. It's acting as full-on performance. When this brand of manic extroversion worked for the character, then Downey seemed well-placed. Otherwise, he's a distraction.

Certainly, there are aspects of that approach that are well-suited for Tony Stark, a comic book character that was inspired by the inexhaustible audaciousness of Howard Hughes. Even then, Downey's familiar tricks are tempered. My temptation is to say that he's more relaxed than usual, but his most trying performances exhibit a distance and even disregard for the material at hand so that theory isn't quite right. Instead, I think he's more focused and committed, playing with his familiar style in a way that doesn't sacrifice the integrity of the character and adds gravity when the confidence gives way to fear, uncertainty, guilt.

Downey's acting is the key component to Iron Man's relative success as a film. Director Jon Favreau also merits accolades. His third big-screen directorial effort, following the kid-skewing Elf and Zathura, is nicely deft visually. He handles the big action set pieces with smooth skill, integrates the multiple effects shots nicely and balances the storytelling. It's to his credit that the development of the Iron Man armor is more than prelude. In fact, it's the film most consistently compelling element. Stark works out the details of this unlikely technology in sequences of with and ingenuity. Favreau, along with the quartet of credited screenwriters, manages to make the origin story into something more than mere prelude to the action. It's a vital, engaging piece of the storytelling.

The script has other problems more typical of summer superhero fare. There are multiple plot holes side-by-side with plot points of grinding obviousness. Despite the richness of the main character, the supporting roles are hollow and cliched, a problem accentuated by the presence of highly talented actors in those roles. Jeff Bridges' brimming humanity, Terrence Howard's potent charisma and Gwyneth Paltrow's whiplash intelligence are bleached away by the rote mechanics of their roles. They're interchangeable parts. A construction that's otherwise as sound and thrilling as this should be able to do better. As one of those underdrawn characters says, "Next time, baby."