Let’s begin with a recap of Iron Man 1, not so much the plot (a man puts on an iron suit and beats the bad guys) as what it was that made it so successful, widely considered one of the best comic book adaptations ever.

First was Robert Downey, Jr. It’s almost impossible to remember now that at one time it was almost impossible to imagine that he would overcome his demons to become a star as big as his talent. “Iron Man” was the movie that established him as a major movie star in part because the role was perfectly designed for his slightly strung-out, self-deprecating surface and ferociously intelligent core. He was a surprise. And so was his character — Iron Man was not an established icon like Superman, Spider-Man, or Batman. The freshness added a lot to the movie’s appeal.

So did the mechanical special effects. Director Jon Favreau, previously best known as a director for “Swingers” and “Elf,” turned out to have the heart of a fan-boy. He minimized the computer effects. He got the details right and hit the sweet spot between dedication and irreverence.

In part 2, as often happens with sequels, pressure to repeat and the pressure make everything bigger can throw things off balance. We can’t be surprised the same way; this time we come in with expectations so high they’re almost impossible to clear. And so what we have is an entertaining summer movie that feels more like a bridge to Part 3 than a repeat of what was best about Part 1 with some organic additions. It’s missing the exuberance of the original. There was the audience’s in the pure fun of the film, based on Tony Stark’s in the physical exhilaration of flying, the mental exhilaration of finding a task to engage his mind and spirit so entirely, and the spiritual exhilaration of meaningful and sustaining engagement with the world.

A strong beginning shows Tony Stark (Downey) as something between an evangelist and a rock star, bragging that he has “privatized peace” and refusing to turn over to the US government the secret of his “weapon.” His suit may be made of metal, but his body is not and the same substance which is keeping him alive is poisoning his blood. Stark’s recklessness and impetuousness is escalating and his assurance that he can keep the world’s dangers under control increasingly sounds more than arrogant — it seems delusional. So this is not a good time for him to get some competition. Mickey Rourke shows up as a Russian with a grudge — and his own metal suit which comes with a deadly accessory. Shooting out from the wrists are electrified whips that can slice a car like a loaf of bread. Nick Fury (Samuel L. Jackson) shows up as the leader of SHIELD, a collection of highly talented and trained operatives, to invite Stark to join. Justin Hammer (Sam Rockwell) shows up as Stark’s weapons manufacturer rival. Don Cheadle takes over the role of Stark’s friend Lt. Col. James ‘Rhodey’ Rhodes. Garry Shandling shows up as a Senator who wants Stark to turn over his technology to the US government. Scarlett Johansson shows up as a very beautiful and capable new employee who turns out to have some additional talents and loyalties. Like Hit-Girl, she mows down a hallway-full of bad guys single-handedly. Her curls bounce enticingly and her catsuit fit is even moreseo.

That’s enough for about four movies, and so the movie sags under the weight of all of these characters and exposition before picking up for one last big action scene. Those who wait through all of the credits will get a glimpse of what is in store for the next film. I hope between now and then they remember that less is more.