When Rickon runs off, Bran sends Summer to protect him. As Summer turns, you can see the collar around his neck that wasn't there before.
Around 00:10:00, the horse is about to catch the man's hand with its mouth. On the next shot, the hand is under horse's head.
Catelyn mentions that Jon has "brown, stranger's eyes"; Jon actually has the gray eyes of the Starks, and looks more like a Stark than Catelyn's children. So Jon did not have "stranger's eyes" - he has his father's.
When Bran and Jojen are walking along the road - which is a modern road that has been coated with sand to give the impression of a wild track - and they are discussing the death of Bran's father, the camera drops down at one point and you can see where the wheels of the cart in which Bran is lying have been through the sand already, presumably in a previous shoot or rehearsal.