To muck up the sequel to Iron Man for the hungry legions of metalheads would require mistakes so monumentally stupid that it's barely worth imagining. All that's needed is screens, seats, Robert Downey Jr., the suit, and the CGI, and it's got all of those things in abundance. In fact, it has several suits, as well as a legion of killer robots, Scarlett Johansson in Emma Peel drag, and Mickey Rourke as a greasy Russian bad guy with bad teeth and a degree in physics.

Rourke's character, Ivan Vanko, wants to de-chrome Tony Stark (Downey Jr.), primarily because Stark's father (Mad Men's John Slattery) screwed his inventor dad back in the '60s. There's a lot of back story that bubbles up in this picture, but it really boils down to dueling hi-tech chest bling and a lot of close-ups of Rourke gnashing his metal-lined choppers and pining for his cockatoo. "I want my birt!" he demands, often, and is understandably miffed when they bring him the wrong cockatoo. "Not my birt!"

It might be fair to say that what Vanko really wants is to humiliate the rich, handsome, babe-magnet Stark because he's spent his entire life in a dark, decrepit Moscow hovel with his bitter, dying alcoholic dad. Seems like there's more than a whiff of old-school Soviet Union/American Cold War jealousy at work here. Nevertheless, Vanko does manage to montage his way through the construction of a state-of-the-art Stark-killing supersuit in his filthy living room, pay for a ticket to the Riviera, kill a number of unfortunate race car drivers at the Grand Prix, and get brought in through the back door to work for Stark's wealthiest competitor. You'd think getting bottomless funding, unlimited resources, and a staggering amount of Stark-worthy ass kissing would mellow the guy, but you'd be wrong.

Meanwhile, the rest of the plot spills out in all directions: we discover that beneath that impossibly smarmy exterior, Tony Stark is dying because the element he's using to power his chest thingy is also poisoning his blood. In his darker moments, he despairs that for all his genius, he doesn't seem to be able to invent a better battery.

It seems that Pepper Potts (Gwyn Paltrow), the closest person to Stark, is apparently the only one who doesn't know about his quandary. Potts serves, not effectively, as Stark's moral rudder, and for her services, Stark makes her CEO of Stark Industries. She's flustered and flattered but unaware that he has about two weeks and a couple of suit jaunts left. It's not much of a spoiler to say that in the course of the film Stark comes upon a solution to his health issues, but as to whether he keeps Potts in her position at the end of the movie is not addressed; if not, she'd make a good villain for the next picture.

On his other flank is Scarlett Johansson as Natalie Rushman (from Legal, we're told), who, like Paltrow, is required to look great, and succeeds beyond all reason, but who also manages to kick a lot of bad guy booty because she is in fact The Black Widow, a Russian Bond-era superspy, who actually works for Col. Nick Fury (Sam Jackson), manager of S.H.I.E.L.D., Marvel Comics' in-house Bond-era spy organization. The movie doesn't digress enough to give Natalie/Natasha any back story; they may be saving that for Iron Man 3-D.

And then there's Justin Hammer (Sam Rockwell), CEO of the rival firm that employs Vanko, and Stark's corporate nemesis. Hammer is equal parts Harry Ellis (Hart Bochner), the coke hound from Die Hard, and Carter Burke (Paul Reiser), the company prick in Aliens. The difference between Stark and Hammer is that while both men are engaged in creating ever more sophisticated high-tech weaponry, Stark at least has a degree of wit and a rare talent for screwball-speedy repartee. Also, Stark wears his weapons.

Stark revealed his secret identity to the world at the end of the first movie in a press conference, of course, and it figures that a government subcommittee spearheaded by Sen. Stern (the ever-whiny Garry Shandling) is demanding that Stark turn over his technology; it gives us a scene that acts as a parody of the moment in The Aviator when Howard Hughes (Leonardo DeCaprio) defied the smarmy senator played by Alan Alda. (Stan Lee, co-creator of the original comic book, has been quoted as saying that Stark was originally based on Hughes)

Both scenes function as a burlesque of patriotism and politics, and to underscore the point, there's a moment in Iron Man 2 when Bill O'Reilly barks out a soundbite from a nearby television, criticizing Stark for being unpatriotic; in effect, it's O'Reilly mocking himself, as clueless and artificial in movie fiction as he is in television fact.

In this scene and throughout the film, Stark showboats mercilessly, and with Downey driving the dialogue, it's at least as much fun as the action sequences. (Imagine how much more entertaining Christopher Nolan's Batman films would have been if Bruce Wayne had had some of Tony Stark's wit -- or, really, any wit at all.)

The difference between the two Iron Man movies is that while it's the same glib arrogance that sold us Stark in the first picture, and put Downey in that expensively tailored hi-tech franchise, the only thing that keeps the character from stepping over into insufferability in the sequel is his illness.

Iron Man was a second-tier character when he premiered in 1963 in Tales of Suspense comics, one of the runts in the litter that birthed the Fantastic Four, Spider-Man, The Hulk, Thor, and the rest. The stories were written and drawn by the B team, Larry Lieber (Stan's brother) and artist Don Heck, rather than Lee and Jack Kirby or Steve Ditko. It was a very odd bird, and it had the industrialist, Stark, captured by a Vietnamese warlord and dying from shrapnel in his chest. With the help of another imprisoned scientist, Stark invents a device that kept the shards of metal from penetrating his heart and while they were at it, the two built a huge, gray suit of armor that Stark climbed into and used to defeat his captors. (Footnote: America was sending troops and advisers into Vietnam at the time, but no combat units were employed until several years later, in 1965; Iron Man was weirdly prescient)

The concept was a real reach, maybe not as much as Ant-Man, but kids at that time were eating up everything Marvel threw at them, and it gave Iron Man years to evolve; he was probably the most adaptable character in their stable, and he was tech-heavy in the Kennedy-James Bond years, when it really mattered.

What's amazing about the new film is how much it draws on the basic character, his situation, and the era that spawned him. Stark gets hidden information from old 1960s film footage of his father that leads him to a solution for his toxic implant, and Vanko is the child of a '60s Soviet scientist. Secret agents from the most flamboyant comic fantasies that followed the Bond craze are pulling strings all over the plotline. And towards the end, when Stark thinks he's dying and is awash in liquor and self-pity, he throws a party that's loaded with bikini-clad go-go dancers and bimbos, like something out of Apocalypse Now or The Doors.

It's a good cop/bad cop look at the weapons industry that also mocks the military and Congress, even while it seduces the audience with a secret U.S. intelligence organization that knows everything about everybody, has limitless resources, and employs impossibly hot kick-ass fighters such as The Black Widow (also, in the '60s, a defected Cold Warrior). Johansson has the best action sequence in the movie.

There are two major problems with the film that pull it down half peg from its predecessor, and they both have to do with the writing and the directing. The movie's story is impossibly lumpy and so overburdened with side plots and digressions that the only characters we spend any real time with are Stark and Vanko, and Vanko sits out the latter part of the two-hour film. The other characters, including Don Cheadle as Stark's friend James Rhodes, are little more than walk-ons. Cheadle gets to voiceover his scene with Downey when he's in the War Machine suit, and Paul Bettany gets some off-screen action as Stark's electronic butler, Jarvis, but Iron Man 2 is all Downey and CGI.

As for the direction, Jon Favreau (who also cast himself as Downey's bodyguard and chauffeur, Happy Hogan) has handled big action scenes in the past, but he seems to lose energy when it comes time for the Big Payoff, which was also true of the first Iron Man. This time we are introduced to a huge number of military-designated robots, all presumably possessed of specialized programming and weaponry, all designed by Vanko. As soon as they're introduced, no canny audience member doesn't know that the movie is gearing up for a fantastic pyrotechnical showdown. It's the payoff, the big battle before the fat lady (Vanko) steps up. And it's a complete letdown. Favreau doesn't ever give us an opportunity to identify the specific talents of the different robots, doesn't make one set more deadly than another, doesn't allow Downey and Cheadle to step up to any separate challenge. Worse, the action takes place at night, backlit in neon, and the terrible composition and cutting makes what happens very difficult to follow. And the fight is entirely too short, because Favreau wants to get past the robot combat to get Vanko up for his finale. This is bad design, and it disappoints the audience, although a couple of the fight scene hat tricks add some fun to the clash.

Downey's tap-dance banter is most of the show, the action scene in the Riviera that introduces Vanko's armor-slicing whips, Johansson's kung-fu fighting, and Rourke's amazing and unexpected underplaying are all high points, and there is what has become a trademark for the Marvel house movies, the foreshadowing of subsequent movies (Thor, The Avengers).

Iron Man 2 doesn't break new ground; it's overlong, unnecessarily complex, and it shorts key players in the drama, but it's fun enough and more than a little psychedelic. They got what they wanted: a summer blockbuster and a successful franchise, and to that end the picture is exactly what it's meant to be. - Henry Cabot Beck

Mr. Beck straddles the coasts, contributing features on movies, music, books, comics, and other cultural objects to the New York Daily News and many other publications.