I caught this movie with friends and in doing so became probably one of only a very few people to see it without having watched the first "Iron Man" movie. Knowing the basic premise behind the original comic book, though, I found that "Iron Man 2" holds up very well entirely on its own, and as a piece of entertainment is a thorough success with nary a dull moment.

Like any good action movie, I think, "Iron Man 2" realizes it can't consist entirely of action, and this one at times feels just as much like a comedy or political thriller as it does a superhero-based special effects spectacular. That comedy is rooted in and succeeds because of really good character work, particularly with the lead Tony Stark. The script by Justin Theroux (who is, I found to my pleasure, related to the other writers Paul, Louis, Marcel, and Alexander Theroux) shows a facility with pointed, revealing dialogue and a whole lot of wit. This script also seems preoccupied with getting characters to declare -- if not in so many words "Oh, yeah? Well just try and make me!" which is deeply satisfying to empathize with even if it does eventually become a little repetitive as a theme.

Robert Downey Jr gives another simply brilliant performance, and his character seems fully alive as a self-absorbed, witty, arrogant, and super-intelligent jerk of a superhero who knows his own life is about to end. This character is as much of a reason to watch the movie as anything.

There is no attempt to hide the fact that much of the plot and its developments are based on pure technobabble -- a new element is discovered with suspicious ease, computer systems can be commandeered with only a few taps, &c. -- but these are not terribly insulting when left out in the open, and they do not interfere with the political caste that keeps the action story moving. Towards the end things become a little less thoughtful and it becomes harder to invest without a grounding in how the rules work for the new technologies that have been introduced, but it never descends to dullness.

Scarlett Johansson and Samuel L. Jackson do well in their roles but those roles, while significant, are never explained or fleshed out much, and they sometimes seem to be there largely to look impressive each in their own way. Gwyneth Paltrow extends the cast of all-stars with a good performance as Pepper Pots, though she seems a little stuck on the note of "beleaguered." It's a nice surprise to see Garry Shandling show up as a fun comic-relief senator.

This was great entertainment and well ahead of a standard issue genre action or superhero adaptation picture, served effective and real wit, good dramatic sub-plotting, and an extremely memorable lead performance from Downey that does a huge amount to make some scenes that would otherwise be laughably absurd very believable.