Continuity mistake: When Bob and Linda arrive at the Wallace house, the exterior shots show the doorknob on the front door to be on the left side which would mean the door would swing inward to the right. However, when the shot cuts to the inside of the house as the door opens, the door swings inward to the left and the doorknob is now on the right side. (00:59:20)
Continuity mistake: In the scene where Tommy Doyle looks out the window and sees the shape outside of the house across the street, the porch light is off and the jack o lantern is not lit. When he attempts to show Laurie, the next shot of the house shows that the porch light is on and the jack o lantern is lit.
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: When Michael stabs Laurie in her arm the wound doesn't bleed at all, and there's no blood on the knife either. Then when she kneels down to talk to the kids, and in every scene after that, there's a streak of blood.
Continuity mistake: When Michael is at Tommy's school, there are cars parked across the street. When he gets in the car to leave, they are gone.
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: After Tommy breaks the pumpkin, he is now walking on the sidewalk without the books that he was holding before.
Continuity mistake: At the start of the film Michael smashes the window, later on at the school the window is intact.
Continuity mistake: Michael breaks the passenger front door window on the wagon when he takes car, a short time later when he's driving in town the window is not broken.
Continuity mistake: Before Tommy breaks the pumpkin at the school in the background there are 2 kids, one with a hat holding something in his hands which disappears in the next shot.
Continuity mistake: After Laurie gets home and her room she leaves her bag and some books on the bed - they change position between shots.
Continuity mistake: When Bob and Lynda get to Annie's house he leaves the door of the truck open, but when Laurie is on the street the door is now closed.
Continuity mistake: Michael stabs his sister repeatedly. The amount of blood shown on the knife when his parents come home is nowhere near enough for the number of times he stabbed her. (00:06:35)
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.
Suggested correction: This scene jumps ahead as Michael was in the living room waiting for them to finish having sex and the boyfriend to leave.
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.
Suggested correction: She stabs with the hanger, he drops the knife in which she proceeds to stab him in the midsection. Once he was shot by doctor Loomis and disappeared, the end of the movie begins prior to the credits and we see the knife lying on the floor next to the knitting basket.
Continuity mistake: When Laurie, Annie and Lynda are walking home from school, the part where Lynda walks to her house you can see the station wagon on the side of the road behind them. A few seconds later it has moved up the side of the street.
Suggested correction: This is intentional. Many times, even driving, Michel can be seen lurking in the background and following them around in this car. This is mean to create a subliminal element of suspense and unnerving restlessness with him always creeping about.
Continuity mistake: After Michael hides behind a hedge bush and Laurie and her friend go to investigate, the sun changes between shots.
Continuity mistake: Michael is watching Annie in the kitchen. He knocks down the hanging plant in front of the door and it shatters. When Laurie goes to check on her she goes in the same door and the plant is hanging back up. (00:43:21 - 01:12:56)
