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: 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, 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: The young girl walks up to the Myers house near the start. From the view in the house she reaches the door. Camera changes and she's halfway up the steps. (00:13:20)
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: When Lynda is talking about how she forgot her books (at the beginning of their walk home) we see Michael Myers drive by, then speeds up and drives passed a driveway, then it cuts to Annie (Myers is still driving) and she says, "Hey Jerk. Speed Kills." We see Michael driving again and he is just a bit behind the drive-way he drove by before, he should be much farther ahead down the road at the speed he was going. (00:21:35)
Continuity mistake: When Laurie is walking home the sidewalk instantly goes from wet to dry. (00:25:25)
Continuity mistake: After Laurie asks Annie what she is going to wear to the dance (while Annie is driving with Laurie), we see Annie turn the steering wheel to the left, yet the car turns right as seen on the green screen in front of them. As the car is turning right, it cuts back to Annie still turning the steering wheel left. (00:33:45)
Continuity mistake: When Annie drops Laurie off at Tommy Doyle's house, when she walks in their front door it has multiple glass panels, but later it is a solid, plain white door. (00:34:45 - 00:39:55)
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)
Continuity mistake: In the scene when Michael is carrying Annie's body into the house her head is on the left side of his body. After they show Tommy looking out the window they cut back to Michael and suddenly Annie's head is on the right side of his body. (00:55:14)
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 Laurie walks across the street to check on her friends, the porch of the Doyle house has nothing on it. When Laurie runs back across the street and starts pounding on the door she picks up a flower pot off the porch to throw at the window. (01:11:20 - 01:18:30)
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: When Laurie is beating on the door to Tommy's house and telling him to open it, the door knob is on the right side of the door. When it shows Tommy opening it from the inside, the door knob is also on the right side (it should be on the left). (01:18:35)
Continuity mistake: Toward the end of the movie, Dr. Loomis comes up the stairs and starts to shoot Michael six times, sending him spiraling to the terrace. Take notice that Michael is about to go over the ledge of the terrace head first. In the next shot it shows him carefully backing off the ledge, while facing the house. (01:26:45)
Continuity mistake: When Annie and Laurie leave the hardware store to go to their babysitting jobs it is broad daylight. When they reach the houses apparently just a few blocks away, it is already dark.
Continuity mistake: During the beginning of the movie, when Laurie is talking to the police officer, the sun is shining bright as if it is a perfect day, then when Laurie walks to her house, the trees look as if it has just quit raining.
Continuity mistake: In the beginning of the movie, Laurie runs into Tommy while she is walking to school, meaning that they live near each other; however, later on in the movie, when Laurie has to babysit Tommy, Annie has to drive her to Tommy's house, which is located on the other side of town.
Suggested correction: The film never says Tommy lives on the other side of town. They were only driving so long as an excuse to cruise around, smoke weed and kill time. Loomis later tells Sherriff Brackett that he's walked 3 blocks from the Myers house and soon after that we see him arrive at the Doyle house, still on foot. Since we know the Strode and Myers houses are within walking distance of each other, we also know the Doyle and Wallaces aren't too much further away.
Earlier on the walk home Annie says the Wallaces are leaving at 7. She later calls Laurie and says she will pick her up at 6:30. Using those times, the ride couldn't have taken for than 30 minutes, part of which was occupied by the stop at the hardware store (when it's still daylight). There's really no way to reconcile this timeline.
Continuity mistake: When Laurie, Annie, and Lynda are walking home from school, the sidewalks are wet. When Laurie is by herself, they are dry.
