Director, Peter Jackson's version of the story has been expanded into three films of which The Hobbit: An Unexpected Journey is the first. (to be followed by The Hobbit: The Desolation of Smaug (Dec 2013) and The Hobbit: There and Back Again (Jul 2014)).
Warning: What follows isn't so much a review of the film, rather it's my thoughts after seeing the film. There could be spoilers ahead. Don't read if you haven't at least read the book and don't want any major plot points revealed before you've seen the film.
Back to the film...
Unlike the individual films in The Lord of the Rings Trilogy the end of this film is a little more abrupt. Like they're making this new trilogy as one big film and just looking for the most convenient place to cut it. Hence you don't get any plot lines resolved... and won't for potentially a year and a half when the third movie comes out in 2014. The movies in the original trilogy hold up better as stand alone films where as The Hobbit doesn't at all.
This first installment is relentless with the action sequences, only really slowing down during the scenes in the Shire where Gandalf and his troupe of dwarves are trying to convince Bilbo to join them. Even then the majority of scenes are very busy with a lot going on. The sequence with the dishes being cleaned (supposedly), whilst fun and funny, seemed exceptionally out of character for a bunch of dwarven warriors more accustomed to camping and out door life than table manners and etiquette.
Speaking of the dwarves, something that bugged me from the start is that many of the dwarves aren't true dwarves. They're properly proportioned, but tiny men, particularly the leader, Thorin Oakenshield. It's only when you stand him next to Gandalf that you get a sense that he isn't just a normal sized human.
Thorin is supposedly a legendary dwarf warrior who's on a quest to reclaim his people's lost city of Erebor. Lost in the sense that the dragon, Smaug, kicked everyone out and now calls the place home (as opposed to lost - can't remember where it is). Thorin spends a good part of the movie telling Bilbo he doesn't belong in the group due to his inexperience and preference for the quiet life, yet it is Thorin who is the biggest obstacle to his group's success for most of the film.
He refuses to seek Elvin help to read the map they are carrying and he single handedly launches an attack on an Orc leader who, the entire group, only moments, earlier were trying to out run the leaders army (that are still in pursuit when Thorin launches his attack). As a result he is nearly killed were it not for Gandalf's giant eagles, saving the day.
(And why does Gandalf make everybody walk most of the way in yet another movie where he has flying eagles? All the trouble with Orcs, trolls, Stone Giants and goblins could have been avoided just by flying to Erebor).
For the most part this is an enjoyable movie with some really good humor and interesting villains. It's let down a little because, although we are introduced to most of the thirteen dwarves individually, you never really get to know any of them beyond Thorin. In fact, when I came out of the film I couldn't even name a single dwarf in the party. As a result you're constantly looking towards Bilbo and Gandalf as the familiar characters in the group.
The action, as I said, is often relentless, coming at you with hoards of pursuing warriors, thick and fast. Particularly in the Goblin lair where the group's escape crosses into 'Indiana Jones' territory (i.e. beyond belief even in this fantasy world). Often I felt I was in a video game shooter, where it's common for hoards of monsters to attack the game characters.
Clearly Peter Jackson is trying to expand this story to tie in more closely with the Lord of the Rings story by bringing in characters like Frodo, Saruman and Galadriel - all making an appearance even though none are in the original book. It feels like his intention is to weave some of what transpired in the original three films into the Hobbit as the beginnings of what is to come (much like Bilbo's acquisition of the ring).
Overall it's a solid start to the series, even if it comes across a little bit more of the same, rather than anything particularly new. As someone who likes Dragons, Smaug is really the draw card for me. This movie paints him as probably one of the most formidable dragons ever to appear in a film. That's what is really going to get me back to the next and probably the third installment.