Continuity mistake: When Sir Didymus threatens Ambrosius with no food to stop his retreat, as the dog walks back into the shot you can see the gray and white mixture on his head. In the close up, the dog's head is all white.
Other mistake: As the cannon the Goblin army brings rolls to a stop, the smoke jet used to simulate shots is visible.
Continuity mistake: The two-headed axe the gate guardian grabs wasn't there when the gate closed.
Continuity mistake: As Ambrosius goes to cross the rocks, he switches from having gray and white on his head to all white, then back.
Continuity mistake: As the white owl flies in and around the room, it is flapping wildly, but the owl's shadow is flapping at a considerably slower speed. (00:11:50)
Continuity mistake: When Sarah and her stepmother are arguing at the start of the film, Sarah's hair is completely soaked from the rainstorm, but a few minutes later, when she's at her vanity table and her dad is talking to her, her hair is completely dry, and there's no way she could have dried it that quickly, even if she used a hairdryer.
Visible crew/equipment: Just after falling into the Bog of Eternal Stench, the duo are moving along the ledge. As it breaks away, there is an overhead shot where you can see a white and blue piece of equipment at the top left corner of the shot. I don't know what it is but it's not in the next shot so it's not something natural to the Labyrinth. (00:55:45)
Continuity mistake: Towards the end of the "Chilly Down" scene, the firey with the long thin mouth and ponytail on the top of his head jumps on Sarah. The others gather around her. Then the chubby firey says, "Come on, Come on!" calling over another firey; however, all five fireys are in the shot around Sarah. The following shot is of the top half of a firey bouncing over on his hands, but this is the same firey that already jumped on Sarah and is still on her. (00:53:10)
Continuity mistake: When Sarah kisses Hoggle, they fall through a hole and end up in the Bog of Eternal Stench. They walk the narrow cliff for a while and then Sarah falls onto solid ground and finds Luto right there next to her. Then Hoggle falls. Somehow, without Luto moving, Hoggle ends up under Luto. Luto never sits down. He is pushed to the ground when Hoggle falls on top of him. His butt is on the floor before Hoggle lands.
Other mistake: When Sarah is at the end doing her speech with David Bowie in that upside down world and is meant to recite the speech word for word, she forgets the line "To take back the child that you have stolen" Instead she skips right over the line and says, " I have fought my way here to the castle beyond the goblin city - - missed line - - for my will is as strong as yours...etc. Etc."
Continuity mistake: As Ludo pops up in the tower of the house in Goblin City, the roof goes over behind him and stops as if on a hinge. A moment later as he calls the rocks, the roof is missing.