Let's see what was added or twisted.
As far as I can see it was -
1. the
dwarves don't have coloured beards (can't say I miss that)
2. the dwarves don't carry a variety of musical instruments (can't say I miss that, either. It would have been awkward to carry them on
ponies. Even
Tolkien himself never mentions them again, maybe they left them at
Bag-End?)
3. The dwarves help themselves to
food instead of asking
Bilbo to play host and serve them (though they politely offered THEIR serving to him in greeting). This does alter the story-line, for it alters Bilbo's standing with them. He is really more of a servant to them in the book and more of a pet in the film.
4.
Thorin is made into eye-candy for female audience and warrior-role-model for the male part. Lovely, but out-of-canon.
5. The dwarves really despise Bilbo, at least Thorin does so openly. They don't expect him to come at all, while in the book they expect him to arrive at a meeting-point set by them - and punctually. See N° 3.
6. The whole AZog-plot is pure JAckson-fiction.
Azog did kill
Thror, but not in battle, and he himself was killed by
Dain afterwards. He just serves to give the bad guys a recognizable face. The book does not really have personal bad guys, it's just "the
goblins" - an amorphal mass - and "the Necromancer" on the outskirts of the story, but with no real significance for THIS one. Remember, it's a children's book. It was meant to be thrilling when read before bedtime, but not to cause nightmares. Azog really serves to embellish Thorin's background, the alluring aura of the desperate, flawed but heroic character part of which is due to a hard childhood (home sacked by a
dragon, help refused by a god-like figure like
Thranduil, grandfather beheaded before his eyes, father driven into madness - it would make for a couple of sessions with an able shrink). I must admit I totally fall for that in the film - but out-of-canon as can be. (The Azanulbizar episode also makes for the first superfluous fighting-scene in the movie. A few seconds less dwarves being tossed by
orcs wouldn't have harmed the plot)
7. Rhadagast - he is obviously an addition, He is mentioned in The
Hobbit but never appears, and he appears in
The Lord of the Rings, but only briefly. He may be meant to add an element of humour the film hardly lacks without. I like him, especially his house which looks uncannily like
the one my family provides for me (or I for my family, well, we live in it together), but for a purist - out-of-canon and out-of-the -question.
8.
The Trolls tricked by Bilbo. Obviously meant to bolster up the antagonistic Bilbo-Thorin relationship (I am waiting for fanfiction pairing them in a slash-story. SO NOT!), and add some humour (Worms!), while in the book it really shows
Gandalf's ability and also, for the first time, introduces his connection with
Rivendell. BTW - that Gandalfs walks out on them because he quarreled with Thorin is also out-of-character and sheds a different light on the wizard altogether. In the book he is much more aloof and independent, while in the film he acts like the true leader of the endeavour. I'm curious if and how he will leave them on their own at the fringes of
Mirkwood.
9. Thorin, and dwarves in general, being antagonistic to Rivendell. That there is scarce love between
elves and dwarves Tolkien mentions several times, but at least in The HObbit he gives no reason (except that elves make fun of beards). Thranduil did not appear at the sacking of
Erebor and the dwarves gladly accept the hospitality of Rivendell and spend a very refreshing spa-time there.
10. The Orcs specifically hunting them down for personal reasons. See N° 6. Next lengthy fighting scene. And a lot of orc-talk, a language Tolkien never developed in such detail. I often think it must be tedious to be an
orc in the movie. No fanfictions, no merchandise, no fan-clubs, no sticks hidden in cornflakes-boxes with your picture, *sigh*...
11. I must say,
Goblin Town I like a lot and it prettily puts into pictures what is words in the book. I found it a bit long at first, but thoroughly enjoyed it in HFR.
12.
Gollum would have been quite different if we hadn't seen him in The Two
Towers. Gollum in the book is just plain dark and evil-minded. Andy-Serkis-Gollum is able to arouse pity not only in Bilbo's heart but in the audience's, too. There is nothing humourous about Gollum in the book and he never appears again after Bilbo escaped from him. So, everything shown to embellish this character is drawn from The Lord of the Rings and pays tribute to the chronology of filming the
books.
13. The whole climax at the cliff. Bilbo neither plans to leave the dwarves because his feelings were hurt, nor does he come back because he suddenly empathizes with them. These are worthy and suitable emotions especially for a time that sees a lot of uprooting and displacing of people and has to face the subject of "Home" in less romantic circumstances - but it is out-of-canon twice squared.
14. The scene with the
wargs and the burning pine-tress and all. Very dramatic in the film, rather comical in the book (remember, it's just the middle of the book, not the concluding scene of the first film) complete with a goblin-sung song. In the film: Lots of action, lots of special effects (did you know there were only two
eagles filmed for the animation? The leader's name is Mina, a very pretty female golden eagle), lots of emotions, beautiful emotions - but not in-canon at all.
Okay, that's my view of alterations. I must say that I like most of them in the movie, but then, I'm not a purist in that way that I expected the film to be the book set to moving pictures. The way the film altered the story makes me enjoy the book more, because I can add the pictures and emotions to the otherwise very little individualized dwarves, and knowing the book makes me enjoy the movie more, because I know what it REALLY was. Makes me feel vastly superior to all those kiddies ooing and aaahing in the cinema at scenes they barely understand ;*)