In terms of structure, we start with a prologues describing the fall of the Dwarf Kingdom of Erebor (The Lonely Mountain), when the dragon came (although we don't see much of him, except for a tail or a wingtip here and there), and the following diaspora of the Dwarf people, under the leadership of Throin (?), the grand-son of King Durin. We get a bit of an explanation about why the Dwarves hate the Elves so much: they didn't help them in their times of need, neither in Erebor nor in Moria. Nice glimpse of King Thranduil of Mirkwood, riding a giant moose, too.
The main plot is framed by having old Bilbo reminisce about his life and adventures, just before the party at the beginning of Fellowship of the Ring.
Dissolve to: young Bilbo and his first encounter with Gandalf, and subsequently with 13 more or less misbeaving Dwarves. I was a bit afraid of the singing numbers, but the "that's what Bilbo Baggins hates" song is quite nice as an Irish jig, and thankfully rather short. The sing about the fall of Erebor, however, is really goose-bumps-inducing. Definetely have to get the soundtrack. (a lot of the musical cues will be familiar from the LOTR trilogy)
Apropos Dwarves: I'm not sure if I'm totally happy with their looks. While Thorin and Kili look totally human, and quite attractive, some of the others look like they're coming straight out of the Asterix comics. Maybe the Dwarf race has a lot of diversity, or they start growing their nose and ears and hair excessively as they get older? It's a bit inconsistent. I really liked Balin, he's a lovely character, and the most fatherly and supportive of them all. In a way, he is as important as Thorin in keeping them all together.
The company then sets off, and encounters the Trolls, which is quite nicely done. They find the swords in the troll cave, as in the book. In a positive change from the books, Gandalf does not claim that he needs Elrond's help to read the runes on the swords, but to decipher the map to enter the Lonely Mountain. I've always found it unrealistic that Gandalf would not have been able to read what's written on the swords...
We are also introduced to the wizard Radagast the Brown, played by the former Doctor, Sylvester McCoy as a lovely, weird old guy, who, at first sight seems a bit simple, living in his hut and caring for his animals (hedgehog scene!), but is revealed to have a good common sense and no small amount of power. He tells the company that the old forteress at Dol Guldur in the Greenwood seems to be inhabited again, and that the wood and its creatures are sick. The Dol Guldur scenes are really creepy.
In Rivendell, Gandalf inexpectedly meets the rest of the White Council, Galadriel (who has perfected the art of elegantly turning on the spot), and Saruman, who thinks that they're all exagerating. Signs and portends, eh?
After Rivendell, there's a rather bizarre scene in which stone giants throw gigantic rocks at eachother. I honestly can't remember if that was in the book...
After that, they get trapped in the goblin caves. The design is really nice and complex, and the Goblin King is great (by which I mean, utterly disgusting but oddly charismatic).
And, most importantly, Bilbo meets Gollum, finds the ring, and they have the contest of riddles, which is keeping close to the original, and thus quite long. On the other hand, I have no idea how else one could have done it.
After having escaped the goblins, the company is ambushed by the warg-riding orcs, under the leadership of Thorin's old nemesis, Azog, and they are rescued by the Eagles, which looked really nicely realistically animated this time. Although, it's not very nice of them to rescue people and then abandon them on a mountaintop in the middle of nowhere...
Then, we get a nice view of Smaug appearing from out of a drift of gold coins, and opening his eye...the End.
In general, I really liked it, especially the beginning and the inclusion of all the material from the LOTR appendices, because I just love worldbuilding, and the intricately crafted background story of Middle Earth. As far as I'm concerned, they should film the Silmarillion. It does have some lengths though, where the company basically wanders from battle scene to battle scene: trolls, goblins, and again and again the ubiqitous Azog. The secind half could have used some more non-battle related plot.
Can't wait for the next one though

8/10