Continuity mistake: In Nancy's final showdown dream, she goes down to the cellar, then goes to open the door which leads to the boiler room. When she opens the door it's hinged on her right hand side, yet when the shot changes the door is now hinged on her left hand side. (01:13:25)
Continuity mistake: When Krueger smashes his arms out the front door window, large pieces of glass are still hanging in the window, but in the next shot, as he pulls Nancy's mother through, all the glass has disappeared. (01:25:10)
Continuity mistake: Keep watching when Glen sneaks through Nancy's bedroom window for the lighting in the bedroom. When the exterior shots are shown the light is always on but it is sometimes off inside.
Continuity mistake: When Freddy jumps out from behind the tree in Tina's dream, his glove is on his left hand then it cuts away and back it's now back on his right hand. (00:15:50)
Continuity mistake: When Nancy is at her bedroom window, she says "OK Krueger, we play in your court" and she is holding her alarm clock. She then pulls down the blind, then when it cuts to inside, Nancy is walking over to her bed but isn't holding her alarm clock. If you look, the clock is on her bedside table, but she doesn't put it there. (01:11:25)
Continuity mistake: After Nancy wakes up from her nightmare in the dream clinic, her mother discovers her arm is scratched. The tape that was on Nancy's chin has gone, but returns in the next shot, only to disappear in the next. (00:48:50)
Continuity mistake: After Nancy pulls her phone out in frustration, she wraps the phone cord around it, and places it on her bed nice and neatly. But in the next shot of the phone mysteriously ringing, the phone is in a different position and the phone cord is wrapped around the phone differently. (01:03:50)
Continuity mistake: In the boiler room Nancy finds Glenn's bloody headphones. As she raises them up from the ground, between shots, the way she holds them changes. (01:16:30)
Continuity mistake: When Nancy is in the boiler room towards the end of the movie, Freddy suddenly jumps out and scares her. In this shot Freddy is wearing his hat. Earlier in the movie Nancy took the hat from him. After the shot where Freddy jumps out at her with his hat on, the next scene shows him chasing her down a staircase without his hat. (01:20:09)
Continuity mistake: When Johnny Depp is talking on the phone with Heather, he lifts his bedroom's curtain in order to see her (since they live right across the street), pushing it up to his right. But when they hang up, he pulls the curtain back from his left. (00:59:10 - 01:00:50)
Continuity mistake: When Glenn is in Nancy's room to wake her up, she awakes from the nightmare, her mother comes to the door and Glenn goes out the window. Nancy shuts the window behind him. After her mother leaves, the window is open. (00:40:50)
Continuity mistake: When Nancy gets out the bath, and after her mother leaves, she locks the door then leans back on the sink. Between a wideshot and following closeup, as she leans back, the way her towel and bathrobe are positioned (around her neck) changes. Also, into the wideshot she crosses her arms yet it the closeup her left hand is up by her shoulder. (00:32:45)
Continuity mistake: When Nancy is in class, the teacher walks around the room and we get a good look of everyone in their seats. Then she asks one student to read in front of the class. But the student who gets up and reads wasn't who was sitting there in the previous shot. He is a different person, and is also wearing different clothes. (00:22:15 - 00:23:00)
Continuity mistake: In the bath scene, Nancy is falling asleep and is awoken by her mother then starts falling back to sleep and her inflatable pillow is roughly 8 inches above her head. When the shot changes to face her, the pillow is now below her head.
Continuity mistake: In one scene Nancy's mother is pouring herself a drink, then Nancy enters the room and she switches off the TV. Then Nancy and her mother start talking about going to school, and behind Nancy's mother on the worktop, a white alcohol bottle can be seen. But after their conversation when Nancy leaves, the bottle of alcohol is gone. (00:19:40 - 00:20:30)
Continuity mistake: Freddy tears open Tina's shirt. When she's being dragged up the wall, its buttoned back up. (00:17:20)
Continuity mistake: When Nancy is by the door, listening to the racket going on whilst Tina's being killed, her boyfriend sneaks up on her, and she says "Oh my God. You scared me." and she grabs her cheek with her hand, and starts to brush her forehead. But in the consecutive shot her hand's down by the wall. (00:17:20)
Continuity mistake: After Nancy gets out the bath, the big mirror goes from having slight condensation on it, to being covered in condensation between shots. (00:32:40)
Continuity mistake: When the cross falls off of the wall, Nancy rolls over in her bed and stretches her left arm to get it, with her right arm under the covers. Then as the shot changes, Nancy's right arm is resting on the pillow, by her head. (00:11:45)
Continuity mistake: Glen is tackled by Rod in the back yard of Tina's house. When he gets up, a grass stain is on the back of his vest, but it's gone when he kisses Nancy. (00:09:55)
Answer: The scene you are referring to is a dream sequence. In dreams everything is different and how they change throughout the movie is no mistake.
SAZOO1975