Continuity mistake: The Myers' house is close enough to be walking distance from where Laurie lives. Yet at the end of the movie when Loomis notices the station wagon right down from the Myers' house, Loomis himself is a mere walking distance from the houses at which Laurie and Annie were babysitting. This is impossible since we were already told the street where the babysitting was taking place at was on other side of town from where Laurie lived.
Continuity mistake: When the girls are walking home from school, Annie says that she is babysitting Lindsey Wallace and Laurie says she is babysitting Tommy Doyle. Laurie also claims that the Wallace's and the Doyle's house are 3 doors down, but when Annie drops Laurie off the houses are right across the street from each other.
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: 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: 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)RLN
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: 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: 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)Tina Gilliam