Revealing mistake: It is obvious when the owl, that attacks Sarah, is a puppet and when it is a real owl, in consecutive shots. It is also obvious when the snake, that Jareth tosses at Sarah, is real and is a fake in subsequent shots. It is also very apparent when Sir Didymus' dog, Ambrosius, is a real Sheep Dog, or is a puppet Sheep Dog, in consecutive shots as well. (00:11:50 - 01:21:25)
Continuity mistake: The house that Ambrosius runs into has a small metal pole with thick rope tied around it very loosely. However when Sir Didymus is at the door, telling him to unlock it, the rope is now tied around the metal much more securely and is differently positioned. (01:19:10)
Continuity mistake: When the gang encounter the large robot, as the robot forms together, you can see there is a big axe leaning up against the wall, to the right of the robot. The robot then bellows "Who goes," for the first time. Then it cuts to Sir Didymus barking and then in cuts back to the robot taking two steps forward - in this shot, the giant axe which was propped up against the wall, has gone. It then returns in the following shot. (01:12:50)
Continuity mistake: When Sarah first sits by the worm, and the worm says "'Allo" you can see that all the bricks of the wall are the same dark brown colour. But a bit later in one wide shot when he says "Yeah at's right" the brick behind the worm has changed to a dark yellow colour. (00:19:30)
Continuity mistake: In the Goblin City, the guards emerge from behind the walls, equipped with weapons and ready to fight. Sarah, Hoggle and Ludo run away, but Sir Didymus turns and yells "Right, charge!" But in the next shot Ambrosius cowardly runs away. Between these two shots, the actual clothes themselves which hang from the line above them change, and their positions differ as well. (01:17:25)
Continuity mistake: When Sarah meets the two guards, in a wide shot the blue guard says "One of them leads to the castle at the centre of the Labyrinth..." as he says this, the other red guard has his head sticking out from behind his shield. But in the next shot as the blue guard says "..and the other one leads to..." the red guard now has his head under the shield. (00:26:10)
Continuity mistake: In Goblin City, after the boulder positions itself on the edge of the wall, it falls on top of a talking gun/cannon, smashing it to smoldering bits, and it says, "Hey, no problem," in the close-up. In the next shot, as Sarah runs up the step to shout for Sir Didymus, the smoldering cannon bits on the ground are quite different. (01:26:05)
Continuity mistake: When Sarah first meets Hoggle, he's going for a pee in a pond. In one wide shot, the water in the pond is moving vigorously, but in the next wide shot, the water has pretty much settled. (00:14:30)
Continuity mistake: After Sarah rescues Ludo, she approaches the "two ugly characters" on the doors. In the close-up, as it pans from one door to the other, the vines that hang between the two doors differ from the previous and following shots. (00:45:05)
Continuity mistake: When everyone from the labyrinth fills Sarah's room, Didymus says "I say, does anyone want to play a game of scrabble" and he has a party hat pulled well over his head. but in the next shot the party hat isn't pulled over his head, but is sitting on top of his hat, which allows the shot of it falling off of his head. (01:32:15)
Continuity mistake: When Sarah approaches the empty crib, the pillow is semi-upright at the corner of the bars behind it and she pulls away the blankets letting most of the mattress show. However, as Jareth's shadow is seen on the floor entering the doorway, the blankets cover more of the mattress and the pillow is now flat and centered. (00:11:20)
Continuity mistake: When Sarah and Hoggle run, as the cleaners race up the tunnel, Hoggle trips and Sarah helps pull him up. In the shot from behind Sarah holds his arm with her right hand and pushes on his back with her left hand. Yet in the consecutive shot facing the cleaners her left hand holds his hand as they begin to run. (00:36:05)
Continuity mistake: When Sarah and Hoggle slip off the ledge, at the Bog of Eternal Stench, they land on Hoggle, causing him to fall on his butt in front of particular rock face. However, in the following shot, before Ludo stands to release Hoggle, he sits about five feet further down. (00:56:20)
Continuity mistake: When Jareth first appears at the open bedroom doors, the branches and leaves are seen outside behind him on both sides of the doorway. As he and Sarah start to speak, the shrubbery changes between the following close-ups and semi close-ups of Jareth. (00:12:00)
Continuity mistake: The length of Sarah's nails change considerably between certain shots in this film. For example, after biting the peach she puts her hand on the tree and her nails are short. Upon returning to her home she runs up to Toby, strokes his face and her nails are long. Then, in her room, when she holds the clipping, puts it and the music box, etc. in her vanity drawer, her nails are short again. (01:04:35 - 01:33:50)
Continuity mistake: When Hoggle says, "It's Hoggle. And don't say I didn't warn you," in the next shot Sarah begins walking down the path, and passes a particular piece of stone wall with mossy eyeballs (also visible in an earlier shot). Two shots later, after Hoggle slams the doors, Sarah, who is startled by the slam, is back at that piece of wall nearer the doors, and the stones and mossy eyeballs differ as well. She takes a moment, then starts walking again. (00:17:50)
Continuity mistake: When Sarah is sitting at her vanity table, in one shot she is holding her lipstick by her face. Then in the next shot she picks up her Labyrinth book. You can see the lipstick standing upright on her vanity table, but between those two shots Sarah didn't have enough time to put the lipstick down. (01:10:10)
Continuity mistake: Near Toby's crib there is table with a tea/coffee set with cups and other items on it. These things change their positions on the table in different shots. When Sarah holds Toby up high and asks the Goblins to take him away, when Sarah walks into the bedroom and says, "Toby, are you alright?" then when Sarah gasps at seeing the owl. (00:08:55)
Continuity mistake: Sarah awakens on the trash heap in the close-up and after she looks at the peach she is seen again on the pile of trash. Before the Junk Lady moves, the things around her are quite different in both shots. (01:10:00)
Continuity mistake: When Sarah enters the replica of her bedroom in the junkyard, she has no lipstick on. As she is sitting at the vanity table, a fresh coat of red lipstick has been applied to her lips between shots. She does hold a tube in her hand, yet she never applies any. Then as the replica bedroom begins to collapse, it is apparent that there is now no lipstick on her lips. (01:10:00)
Answer: The necklace is a symbol of Jareth's power throughout the story. All the time that Sarah is in the Labyrinth, Jareth has more power than her, because she doesn't really know what she's doing, and isn't taking one particular path, just getting lucky at the right times. At the end, as we all know, Sarah triumphs, and Jareth's necklace changes to admit his defeat.