Continuity mistake: Feng falls alongside the tall building for approximately 8 seconds, getting close to the ground before pulling his parachute's cord. After Feng pulls the cord, he and the parachute are closer to the top of the building than the bottom. (00:14:10)
Other mistake: Throughout this, a running gag is that Fred can't drive stick/clutch. However, in "What's New, Scooby-Doo?" Series 2, Episode 6 "A Scooby-Doo Halloween," he yells at Shaggy that he's riding the clutch too hard at the beginning of the episode. If the Mystery Machine has a clutch mechanism, he would know how to drive stick/clutch.
Continuity mistake: In the prologue, the Nazis storm the Bresson residence. The elder Professor Bresson is sitting at his desk, back turned to them. There's an open fountain pen next to him, right by a paper sheet, but when Bresson answers rather defiantly to the bad guys, the paper sheet suddenly has disappeared. (00:02:15)
Deliberate mistake: The prisoners in the dark dungeon would not be able to read the letter (to Miss Dudley from Jason Flemyng that the carrier pigeon had) or see such a clear reflection by pouring water on the stone floor and holding the letter (written backwards) by the water. The room was suddenly lighter when doing so, but it wasn't clear where the light was coming from. Also, sunlight coming through the small window would not beam straight down along the wall. (00:07:23)
Continuity mistake: Xiao Meng spent some time wrapping her father's (Professor Tao) left hand, going around his wrist/thumb and under his thumb (diagonally across his palm). When Tao was blown off the bridge and landed in the dirt, the bandage was NOT wrapped around his thumb (just around his wrist). (01:12:33 - 01:16:03)
Continuity mistake: After the alien abduction, Emmet plans to lead a rescue mission and opens the gate asking "Who's coming with me?" During the sequence, the shadows change completely. At first he is not casting much of a shadow, then it reaches the metal doors, then it stops midway towards it. (00:20:55)
Continuity mistake: At the beginning of the movie, the two knights are walking across the courtyard to get on their horses. When they mention the falcons' names, a young lady wearing an orange striped cape curtsies before them in passing. A couple seconds later during the close-up of girls ogling them from distance, the same lady passes in the foreground, coming from the opposite direction and in a totally different spot. (00:00:55)
Continuity mistake: The protagonists escaped from captivity and managed to return to Harry's palace. Luka decides to leave to go look for his mother. Harry seems to send him off, and he is standing in the middle of the stairs, about 4 steps below the guard. Harry at this point is in close-up; the guard is not visible, and at the next cut somehow Harry shoves him off as if he were standing directly behind him. (00:16:00)
Continuity mistake: When Aunt Sarah arrives, she dumps her luggage in the hands of Jim and then passes him to his right, leaving him between herself and the door. In the reverse shot, Jim is on the opposite side. (00:29:15)