This was always gonna be the tough one for Marvel. Thor isn't a superhero, he's not some ordinary Joe who mysteriously acquires special abilities, he's the Norse God of Thunder and he goes around causing damage with his massive tool. It would have been so easy for this story to have ended up a pompous, camp, silly joke of a film.
What director Kenneth Branagh delivers, however, is a hugely entertaining fantasy adventure/fish-out-of-water comedy that never strays to the wrong side of self-importance or silliness.
Thor is a rock-hard fighter, poised to inherit the crown of his Anthony Hopkins-shaped father, Odin, and become lord of Asgard. Being a bit of a cocky gimp, Thor kinda starts a war against his father's wishes and Odin bitchslaps the superpowers out of him and hoofs him down to earth to mingle with the puny humans. Meanwhile, Odin's other son, Loki is eyeing the throne for himself...
The scenes in Asgard are all CG spectacle and theatrical set-design, but there is an attention to human (Asgardian?) drama that never lets the broad, classical story (father and son, betrayal, exile, redemption, revenge etc) be overshadowed by the digital glitz.
What could have come across like "Krull" with better special effects is actually an engagingly realised fantasy world peopled with generally interesting characters. Chris Hemsworth's Thor is all roaring and cheering and bellowing and back-slapping and hammering, Hopkins' Odin is noble yet world-weary, Tom Hiddleston's Loki is troubled and earnest, and Thor's backing singers Lady Sif and the Warriors Three come off like four buddy musketeers, with Ray Stevenson reaping many of the film's chuckles with his turn as Volstagg, a jovial, gluttonous, Viking man-mountain. Oh, and Rene Russo stands in the background not doing much as Thor's mum.
It is when Thor gets the boot to Earth that the movie really begins to open up, however, as he is discovered by a pretty young astrophysicist (just go with it) and her small team of researchers, comprising crumpled euro-ledge Stellan Skarsgard and peppy jailbait Kat Dennings. Natalie Portman turns in a solid but unremarkable performance as this astrophysicist next-door, but as complications arise for Thor and Loki, it becomes clear that this film is all about two people: Chris Hemsworth and Tom Hiddleston.
Hemsworth starts from the bluster and braggadacio of the Asgard scenes and gradually peels away layers of Godly behaviour to reveal the man - even the boy - underneath. He is equally adept in both the light-comic situations that arise as Thor walks the earth and the hammer-swinging fightoramas, as comfortable with the burgeoning Portman romance as with the fraught relationship with his father and brother. There's a moment where Thor, crestfallen at his lot and apparently trapped on Earth indefinitely, simply asks his brother "can I come home?" in the most heartbreakingly fragile manner. It's a key moment in what is sure to be a star-making performance. Hemsworth takes the most outlandish character and makes him sympathetic, charismatic and even believable. Thor is in good hands.
Hiddleston's Loki, meanwhile, mutates from the earnest counsel of the early scenes into a seething mass of self-loathing and vengeance. Hiddleston prowls around the screen, managing to remain sinister even in some oddball costumes, sneering like a young Jeremy Irons. In fact, the best way to describe it might be that Odin is Mufasa, Thor is Simba and Loki is Scar, and Hiddleston is a worthy successor to Irons' feline manipulator. The boy will go far.
Branagh handles the action scenes with skill, particularly a bash-up with some Frost Giants and a Big Fucking Monster early on, Thor punching his way into a SHIELD lab to get back his hammer (watched over by a mysterious chap with a bow and arrow, comic nerds!) and a showdown with a Big Metal Bastard What Shoots Fire Off Its Head. Occasionally he gets slightly bogged down in the effects and the CG turns a little muddy, but mostly it's solid stuff.
The key to the film is a lightness of touch, striking a similar tone to the "Iron Man" films and boding well for the oncoming cross-over in "The Avengers" (there's a Bond-style "Thor will return" legend at the end of the credits). Branagh never lets the film disappear up it's own arse, tempering any drifts into self-importance with a streak of self-awareness that engages to the end.
So Tony Stark and Thor Odinsson are present and correct. Now we just have to see if Steve Rogers can hold his own.