Revealing mistake: When there is a flashback of Thorin in the war, in the first few seconds, on the left of the screen, there is a man with a shield. He swings it at an ogre and you can see it misses by a good five inches, but the ogre moves his head back as if it were hit.
Revealing mistake: When Gandalf marks Bilbo's door, you just see the outline already marked on the door. (01:15:10)
Answer: In the film, Gandalf tells the dwarves he chose Bilbo because hobbits are light on their feet, and because Smaug would not recognise the scent of a hobbit as he would a dwarf. Also Bilbo is the most adventurous of the hobbits in the Shire. This reason is not in the book but is from the story "The Quest of Erebor" in Tolkien's Unfinished Tales.
Sierra1 ★