Part of why the Thor movies work as well as they do is because Chris Hemsworth really doesn't have to do that much to convince us he's a god. (Or a space sorta-immortal, whatever.) And it's not just that he's got the face of an angel and the body of a titan. He simply has a commanding presence about him, you genuinely trust in his ability to protect us puny Earthlings from the cosmic forces threatening to destroy us. But, and this is a crucial but, his eyes also twinkle with a bit of humor. Hemsworth knows that all his muscly hunkiness and hammer-tossing and whatnot is a goofy lark. And the Thor movies know it, too, which is why they remain the true comedies of the Marvel universe. Which is just fine by me.
Though not quite as sprightly as Kenneth Branagh's original outing, Thor: The Dark World is still a zippy gambol. Well, the second half at least. Which is somewhat strange for a superhero movie. Usually the set-up is what's fun, and then by the time the big climactic action set piece kicks into gear, things have muddied into a senseless clatter. Instead, the beginning of Dark World is a slog of exposition that grows tiresome. We learn about the movie's MacGuffin, some sort of evil weapon that some bad guys want to use to cast the universe into terrible darkness, and there's some strife between wicked Loki (Tom Hiddleston), now in a dungeon in Asgard for his crimes against New York, and his proud, noble family. It's all rather soupy, especially everything involving the villain (a "dark elf," heh) and his nefarious plot. One problem with all of these Marvel movies is that the villains always seem too arbitrary; it's just a fill-in-the-blanks of [bad guy] + [thing he wants]. I know that's true of pretty much all action movies, but particularly in Marvel's world, the stakes never feel quite as high as they should.