Starring Robert Downey Jr. and Mickey Rourke. Rated PG. Opens Friday, May 7

Two years ago, Robert Downey Jr. was a quirky character actor, well-regarded for the detail and charisma of his performances, but still redolent of the sordidness and public ridicule that was the legacy of the gigantic bender that was his 1990s. His casting as Iron Man, a comic book superhero, was seen as a move of some daring, and which received strongly approving buzz from the ranks of Geek Nation.

Iron Man was such a monstrous hit, upon whose mounting revenues Marvel is erecting a multiverse of related product, that now we’re assumed to have seen the first movie. The evidence for this is that the sequel jumps straight into the midlife (at least) crisis of Tony Stark, a man slowly dying of poisoning from the very unit that powers his groovy flying suit.

Unfortunately, this crisis manifests as rapt self-satisfaction and overt cockiness. It’s a reaction that is plausible, but not exactly conducive to enjoying Stark’s company. Even his sidekicks Pepper Potts (Gwyneth Paltrow) and Lt.-Col. James “Rhodey” Rhodes (Don Cheadle) are depicted as a harridan and a sellout to the military industrial complex, respectively. Only the driver, Happy Hogan, has a part more ingratiating that in the original; Hogan is played by Jon Favreau with a giddiness that is overly tolerated by director Jon Favreau.

Further inverting the expected emotional order is the sympathy generated by the ostensible villain. Underplayed to a reptilian extent by Mickey Rourke, still sporting his luxuriant Wrestler bouffant, Ivan Vanko is a genius physicist who is also a gargantuan brawler and well-connected in the Russian mafia, to gauge by his extensive tattooing. To boot, he hates Stark, because Stark’s dad ruined Vanko’s dad over a business ethics dispute. So he builds his own arc reactor and cool (if unfathomably short-range) energy-whip weapon to beat up Iron Man. He’s completely bad-ass—more attractive in some ways than Tony, whose mockery of a Senate oversight committee suggests ominous fascist tendencies.

The Vanko revenge plot leads to where the sequel does improve on the original: numerous fight scenes. There are plenty of mayhemy encounters and explosions, showing where the special effects money went. More eye candy is presented by Paltrow in tight business attire and Scarlett Johansson in a form-fitting velveteen catsuit.

Still, it is at least a little regrettable that a movie that dwells so deeply on heart accessories should find its heroes so disheartened. Matters are clearly meant to be resolved in the forthcoming Avengers, an omnibus sequel to Iron Man, Captain America, The Incredible Hulk, and Thor. (There's also a post-credits teaser, Marvel’s now-standard way of handing off the hype football to its next title, rather like the Bond pics of yore.) But Tony Stark is my well-dressed alcoholic womanizer of lethal capabilities; I hope he feels happier next time.