They say that it's not about the destination, it's about the journey, and that's THOR's biggest problem. There's no plot point in it that can't be seen from space, so how we get there becomes more important. Fortunately for THOR, we get two pretty terrific performances out of Chris Hemsworth and Tom Hiddleston, as Thor and Loki respectively. Kenneth Branagh's direction is at its best when these two are onscreen, because although on paper this may be another superhero movie, no one told these actors, who play their roles with quite a bit of subtlety and nuance. When the film requires it they can go head to head but for the most part it's the quieter moments of THOR that are the best ones.
That said, I think the film suffers from a common ailment of superhero films - pacing. There's a midsection that's fairly bland because we're waiting for those plot points that we know are coming to happen. THOR also suffers the common ailment of origin story movies - you can sense that the movie wants to go bigger in scale but either story or budget constraints are keeping that from happening. Again, we know how these movies work and what's supposed to happen when it happens, but I found myself wanting to be more surprised by the film.
Thor is a braggart, full of pride. Loki, his brother, is quieter, more thoughtful, and jealous of his brother's success. When Thor is about to be named heir to the throne by Odin (Anthony Hopkins), a sudden attack by Asgard's long enemies, the Frost Giants, spurs Thor into action. Against his father's wishes, Thor invades Jotunheim with Loki, Sif (Jaimie Alexander) and the Warriors Three (Ray Stevenson, Tadanobu Asano, Josh Dallas). When Odin pulls Thor and his allies out of the fire, in his anger Odin casts Thor out of Asgard and to Earth, powerless and without his magical hammer Mjolnir. Thor must learn humility and to care for his fellow man. Meanwhile, Loki learns something about his own past, and with that knowledge he decides to take his own kind of power. Thor, with the help of Jane Foster (Natalie Portman), Erik (Stellan Skarsgard), and Darcy (Kat Dennings), must stop his brother's machinations to save both Asgard and Earth.
I do admire what Marvel Studios is doing with THOR and the set-up for THE AVENGERS. It's working very hard at creating this shared universe on film, and as they introduce these different rules of magic in a science-oriented world, Marvel has to be careful not to overplay their hand. But so far they're doing a good job, one that hopefully we'll see pay off in next year's film. My chief complaints about THOR are, once Thor gets to Earth, we're just waiting around for him to basically leave. The Earth scenes are made more palatable due to Hemsworth, who really is quite good. He knows how to bring it down but he also has a significant presence onscreen that you can easily believe that he can do the amazing things that he does.
I think Idris Elba, as Heimdall, the guardian of the Rainbow Bridge, deserves special mention. He's terrific - noble, formidable, and intense. All the fan uproar over his casting is that much hot air. He personified Heimdall and I hope we get more of him in any sequels, which you know will likely come.
But Tom Hiddleston is probably the best performance of the film. It's rare that we see a villain have an arc that is as believable as Loki's - by the climax of the film, you're almost rooting for him to succeed, and that's a big part of why the film works as well as it does. You can see the hurt and pain in his eyes turn to righteous anger and it helps that Branagh has the Shakespearean background that he does, because Loki comes from a long line of those anti-heroes - he's all Iago and Richard III, with a little Cassius built in.
In the end, I think THOR's a good movie. Not without problems, but still a lot of fun. If I had to compare it to the other Marvel films, it's no IRON MAN, but it's well above IRON MAN 2. So far, the Avengers Universe is shaping up rather nicely. If they can stick the landing with CAPTAIN AMERICA, next year's film will definitely have something to live up to.