When our eponymous hero (Chris Hemsworth) arrogantly defies the orders of Odin (Anthony Hopkins), his father and King of Asgard, Odin strips Thor of his powers and casts him out of Asgard to Earth. There, Thor crosses paths with astrophysicist Jane Foster (Natalie Portman) on his path to redemption, which is hampered by his double-dealing brother Loki (Tom Hiddleston).
There are a lot of good things about Thor. The cast as a whole are strong, and feel at home with the combination of the fantastical and real world action. Hemsworth, a relative newcomer, is an excellent choice for Thor, making the hero's journey from conceited hothead to selfless superhero entirely believable. Hemsworth's comic timing is also impressive, providing some real laughs as Thor's old-world Asgardian mannerisms clash with the modern day. The relationship he develops with Jane Foster is touching and authentic, with Portman and Hemsworth displaying pleasing chemistry.
Thor does have its problems, however. Whilst the sections set on Earth are convincing and provide some enjoyable action sequences, the sequences away from our planet are less successful. The realisation of Asgard on screen is laden with CGI effects giving it a somewhat artificial sheen. The film also at times feels a little too much like a precursor to forthcoming film The Avengers. Thor's back story is successfully established, but other characters feel a little underdeveloped. Loki in particular, despite Hiddleston's solid performance, never felt like a genuine threat as the main antagonist. The film's ending has a similar feel to that of Captain America: The First Avenger, in that things are left on something of a cliffhanger that doesn't fully satisfy the character arcs established in this film, which leaves you wondering whether Thor was intended to work as a standalone film, or only as set-up for The Avengers.
As an addition to the Marvel film universe, Thor works and is certainly a worthwhile watch. But it's also yet another example of the problems of superhero origin stories and striking the right balance between including all the pieces of the hero's tale and telling a compelling story in its own right. In comparison with the other pre-Avengers films, it's way above The Incredible Hulk (but then most films are) but never reaches the successes of the Iron Man franchise, and sitting just below Captain America. In the end, Thor is enjoyable, but never outstanding.