In this comic-book-movie sequel, industrialist Tony Stark battles a new electric-whip-wielding enemy, plus the US government, plus a rival weapons maker, and – of course – himself. Iron Man 2 met my expectations as a solid popcorn-movie followup, complete with believable characters, a plausible plot, and lots and lots of action.

Stark (Robert Downey Jr.), revealed to the world as Iron Man in the first film is quickly subpoenaed by Congress, which wants his weapons. Stark, of course, is adamant that the feds not get their hands on, well, his own body. This leads to the introduction of Justin Hammer (Sam Rockwell), who holds many government contracts and who is apparently insanely jealous of Tony Stark's success.

Meanwhile, in a far-off land, a tattooed Mickey Rourke – playing a Russian physicist, no less – plots his revenge on Stark, something about his dad being done wrong by Stark's dad lo those many years ago. And this leads to Rourke becoming Whiplash, a man powered by a device similar to Stark's own chest implant, only with giant electric whips. Neat trick, huh? That the military eventually – okay, quickly – gets its hands on one of Stark's suits shouldn't come as much of a surprise. But in this movie, anyway, the army isn't the bad guy, so there's that. After all, Stark's best buddy is James "Rhodey" Rhodes, played here by the excellent Don Cheadle, who's a lieutenant colonel. And you just know, having seen the first movie, that Rhodey will suit up himself here, as War Machine.

Although the movie gets off to a slow start, focusing a bit too much on Stark the person rather than on Iron Man the action dude, it perks up when other characters enter the fray, particularly Scarlett Johansson as a notary in the employ of Stark Enterprises. (Note: She's not just a notary.) Downey Jr. is amiable as always as Tony Stark, and it's as great of a fit here as before. (Some would say this role represents typecasting for Downey Jr.) Stark is brave but vulnerable, smart but besotted. He's lost without Pepper Potts, his assistant and true love, and their relationship dips and crests throughout the movie as well.

In fact, all returning actors reprise their roles rather well, and most of the new ones immerse themselves in the Iron Man universe seamlessly – including, I should note, Samuel L. Jackson, who barely appeared in the first Iron Man movie but is in several more scenes this time around, as Nick Fury. Yes, THE Nick Fury. Garry Shandling's also on board as an oleaginous senator.

Only real quibble is with Rockwell as the slimy Hammer. At first, this looked like a role more suited to Greg Kinnear – smarmy white dude – which would be beneath Rockwell, who's a strong actor. But later on it looked more like Rockwell was too – pardon me – cute for the role as Hammer, who turns out to be much more ruthless than at first blush. Sam Rockwell doesn't look ruthless at all, and he isn't convincingly ruthless.

Still, quite a bit of fun. There should be at least one more IM film, says director Jon Favreau (who has an on screen role as well, as #1 helperdude Happy Hogan).