Continuity mistake: In the beginning, when the doctor is talking to the new nurse for Michael in the car, the nurse is smoking a cigarette, but seconds later she has just lit one up. If she smokes one in 45 seconds then lights up another she is one worst chain smoker I've ever seen. (00:08:05)
Continuity mistake: In the scene where Laurie comes downstairs after taking a shower, she is at her front door singing to herself and she is looking out a window directly to the left of the door. Then there is a shot of the front of her house outside and you see her exit through the door that had the window next to it, but there is no longer a window there.
Continuity mistake: Laurie's hair keeps changing throughout the movie. Her hair changes from wavy to straight while she babysits the kids. It is wavy again when she is going to Lindsey's house, and straight again when she is running back to Tommy's house. It stays straight until Michael starts to strangle her,where it becomes wavy again, having been straight in the previous shot. It all ends with straight hair. Surely all of this could not happen in a matter of hours.
Continuity mistake: In the beginning of the film when Michael is walking through the house, the clocks have different times on them. After he walks by the clock in the living room, it says 9:40. Seconds later, it strikes ten times.amycamille1975
Continuity mistake: When young Michael Myers sees the clown mask, Judith's clothing is bunched up together on the floor. When he puts the mask on, Judith's sweater is lying separately from the rest. (00:05:15)
Continuity mistake: When Laurie is in the closet she stabs Michael with the hanger and leaves it up there. When they show all the locations at the end of the movie, in the shot of the living room look near the floor up close - you can see part of the hanger there, even though it was left upstairs.
Continuity mistake: At the beginning of the movie the only light on in the house is from Judith's room, which she turns off. Michael is seen walking through a dark house with only the hall light on. When he comes outside after killing Judith every window in the house has a light on. He didn't have time to turn them all on as he ran down the steps.