After Tony has taken Rudolph to a cow in the near-beginning of the movie, and Rookery is driving toward Tony, Rudolph yells "Shut your eyes, Tony!" The next scene shows Tony introducing himself to Rudolph for the first time.
When the Vampire-Boy finds the Game-Boy, the Game-Boy makes sounds although it's off.
When Tony puts Rudolph into the chest at the end of his bed, he climbs into bed with his red T-Shirt on. In the next shot, his red T-Shirt is neatly folded up, and is sitting on the chest, and Tony has now got a pajama top on.
When Tony has a bloody nose his mom has put tissues in it to stop the bleeding. She pulls out one side and says still bleeding so she gets more tissue, while she is rolling it up there is no tissue in that one side of his nose. Then after she is done rolling it up the tissue is back in his nose without her putting it there, then she pulls it out again and replaces it with fresh tissue.
When Tony is talking about vampires in lessons, '300' magically appears on the blackboard. The teacher never wrote it on there.
When Tony throws a stone at Rookery's light to save the Sackville-Baggs, he pumps his arm and says "Goal!", though his mouth clearly says "Yes!" Also, Rudolph, in response to this, says "Wow!", although HIS mouth clearly forms the words "Oh, man!"
When Tony goes down to help Rudolph after he tries to fly out of the window, Tony asks him if he's okay and you can hear Rudolph saying "Do I look it?" but his lips never move.
In the initial scene where Tony and Rudolph are searching for the amulet in Tony's room, almost every line has been dubbed over. Their mouths remain closed.
As the three children are about to shift the lid of the vampire couple's coffin Rudolph counts "1, 2, 3, go" but his lips never move.
When Tony says, "It was," to Rudolph, his mouth remains closed.
When Tony is in the barn with Rudolph, it is dark night, yet set lights and reflectors can clearly be seen, reflected in Tony's glasses.
When Tony is lying on his bed, talking to Rudolph who is resting in his box, the boom microphone's shadow can be seen on one of the light spots on Rudolph's box.