Revealing mistake: Jareth sends a crystal ball to turn into the cleaners in the Oubliette. Right after the cleaners appear, the camera turns to Hoggle and Sarah, where Hoggle says, "Oh no, the Cleaners." Soon after, the two of them start to run. As they start to turn, look above at the ceiling. A light turns on to show them the way out.
Continuity mistake: When Sarah first meets the Goblin King, she has on Camel colored semi-formal flat shoes, but when she starts the labyrinth, her shoes have changed to brown suede loafers. She didn't change her shoes beforehand.
Continuity mistake: During the battle in the Goblin City, a Walking Cannon fires a shot at one of the rocks. When the rock shatters, the roof behind it and a jar at the right edge of the screen suddenly shift their positions - slightly but visibly.
Revealing mistake: When Sarah attempts to cross the bridge and winds up holding onto a tree branch, Hoggle gasps, revealing the actor's face inside his mouth.
Continuity mistake: When Hoggle is taking Sarah out of the oubliette, the lamp he lit goes out quickly just as they exit; yet in the shot of Sarah immediately after she comes out of the doorway, we can see behind Sarah into the oubliette and the lamp is still lit.
Revealing mistake: When Sarah defeats Jareth, you can see levitating arches in the background. If you look closely at them, however, you can see the wires holding them up.
Revealing mistake: When the girl starts walking along the labyrinth check a V shaped tree on the right. She's always walking that very same track revealing the set was small and perspective was achieved with matte paintings.
Revealing mistake: In the Goblin City, toward the end of the fight scene, one big boulder rolls towards a group set up like ten pins. As it hits them, you can see the plungers used to pop the dummies in the air.
Visible crew/equipment: As "Chilly Down" ends, Sarah is pulled up the ledge by Hoggle. When it shows Sarah, and the Fireys flying behind her, above the first Firey that flies up, the wires are seen.
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: During the Magic dance scene Jareth throws the baby up in the air but when he lands he's turned 180ยบ.
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.
Audio problem: Watch Agnes the Junklady's mouth as she picks up Charley Bear. The second time she says Charley Bear before putting it on Sarah, her mouth doesn't move.
Continuity mistake: As Ambrosius goes to cross the rocks, he switches from having gray and white on his head to all white, then back.
Other mistake: As Sarah looks at the opening that she can't readily see, the vine on the right side goes from sharp to blurry at the top of it.
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.
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.
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.
Answer: To add to that, the other door was supposed to lead her to certain death, and technically the oubliette wasn't exactly certain death.