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: When Laurie escapes the house by smashing a window pane, the glass shards disappear instantly in the next shot. (01:17:47)
Continuity mistake: After Tommy breaks the pumpkin, he is now walking on the sidewalk without the books that he was holding before.
Continuity mistake: When Laurie goes to leave the key, the door has two intact glass frames but when the view changes there's only one that's almost completely broken. Later when Loomis enters the house, there's two again, with one only being slightly broken. Also, the frame from the inside looks really small when Michael watches, and we don't see planks nailed across to cut out the view from inside, as well as there being a screen door that isn't there from the outside, but is there when the view is from inside. (00:13:35 - 00:36:40)
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, 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.
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)
