First of all, there is no suspense, no pace to the movie, nothing to give you that nice feeling of holding your breath during the whole movie eagerly awaiting what will come next. No, this was just a waste of 3 hours of my life.
Then the movie itself doesn't make sense, some examples: - the whole group except Gandalf is deep down a Gobelin mine, fighting the king and obviously loosing the battle. Then tadaaaa Gandalf appears, teleported or something, to save them all. And of course after that they have to run for hours to find the exit, instead of taking the path Gandalf took to enter ( or teleport back ). - again in the Gobelin mine, right before the exit, they defy all gravity rules, the king falls down first, then the bridge they stand on (which they use as a skateboard of course), and when they reach the bottom they get crushed 5 minutes later by the king who finally decided to finish his descent... - why did Gandalf call the giant eagles at the end of the trip and not on the beginning? Due to a lack of mots in the beginning area?
And I skip all the parts not in the book, just created to extend the length of the movie, allowing for 3 episodes.
Finally, I must admit the special effects are stunning, but all fights (and there are many of them) have a big problem; either you see the movie at 48fps and you have a big chance of getting sick (just google it) either your eyes will hurt at the end of the movie because of the fast and blurry scenes.