"Iron Man 2" is a polished, high-ozone sequel, not as good as the original but building once again on a quirky performance by Robert Downey Jr. The superhero genre doesn't necessarily require good acting, but when it's there (as in "Iron Man" and "The Dark Knight"), that takes it up a level. Downey here gives us a Tony Stark who is cockier and more egotistical than ever. Or, and here's the key, he seems to be.
-- Rober Ebert, Chicago Sun-Times
If the original was a well-oiled fun machine with Robert Downey Jr. as the rare un-anguished superhero who actually reveled in his powers, the overblown “Iron Man 2” finds our hero clanking his way through tedious subplots and a talky script that’s dangerously low on Tony Stark’s trademark quips... While it has its moments, there are times when I found myself agreeing when the ADHD-addled Tony complains he finds something “boring, boring.”
-- Lou Lumenick, New York Post
As sequels go, this one is acceptable, nothing more, nothing less. With star Robert Downey Jr. and director Jon Favreau back in the fold, this is a haphazard film thrown together by talented people, with all the pluses and minuses that implies... A film that just wants to have fun.
-- Kenneth Turan, Los Angeles Times
Are returning director Jon Favreau and the Marvel Studios producing team buckling under pressure to give the people more of what they think the people want, and make it bigger, too? That's the only reason I can think of for the time and money devoted to loud, long, escalating battle scenes, waged among inconsequential war machines (there's nothing duller) that are themselves merely the products of CG artists — undifferentiated action sequences that stall long stretches of the story and threaten to stomp out the quotient of fun.
-- Lisa Schwarzbaum, Entertainment Weekly
"Iron Man 2" knows how to jump the hurdles and have you smacking your lips for more. For that, all credit to Downey. As Tony Stark, the playboy weapons-manufacturer-turned-pacifist-superhero, Downey never tries to be likable, like Tobey Maguire as Spider-Man, or to throw a pity party for himself, like all the actors who climb into the Batman suit. Downey plays Stark like the horny, hard-drinking, self-destructive narcissist he is. Stark likes his life on the edge. He knows the shrapnel-wounded heart that fuels him is also killing him little by little. And he gets off on it.
-- Peter Travers, Rolling Stone
Well, that didn't take long. Everything fun and terrific about "Iron Man," a mere two years ago, has vanished with its sequel. In its place, "Iron Man 2" has substituted noise, confusion, multiple villains, irrelevant stunts and misguided story lines... Visual and CGI effects are the best and worst thing about "Iron Man 2." The film relies far too much on them. They catch one up in the action, but, unfortunately, nothing else does.
-- Kirk Honeycutt, The Hollywood Reporter