Continuity mistake: When there is a four-way split-screen while they enter the house, the top-left, the bottom-left, and the top-right don't match properly. (00:31:55)
Continuity mistake: At the start just after Willy sees his partner's head in the washing machine, he gets his throat cut and there is blood all over the knife. Later on when Michael is approaching Laurie's room, his knife just has blood on the tip, only halfway up the blade. (00:09:35 - 00:10:20)
Continuity mistake: When Sara gets locked in the closet after the mannequin falls on her, we see Rudy's fist bust through the closet door, as if there were no other way it. In the next shot, the closet doors are wide open.
Continuity mistake: Throughout this entire film, the interiors of the Myers' house are huge, compared to the small two story frame house exterior.
Continuity mistake: When Freddy rendezvous with the gang, Jen's hair when she is applauding at the back is tied in two scruffy bunches sticking out. A couple of seconds later, she has only one bunch tied. From then on, it is tied in two bunches. (00:21:30)
Continuity mistake: When Michael Myers is holding the tripod to impale the crewman, the length of the sharpened end changes in length and shape numerous times. First, it's wider and smaller. Then it's slightly longer and narrower. And when it's finally through the victim, it's long enough to go through the neck and into the adjacent wall.
Continuity mistake: When you see Deckard is in his room with his friend the second time Deckard is relaxed,leant back on his chair with his cheek resting on his fist but in the very next shot he is typing on his computer. (00:25:25)
Continuity mistake: When Michael is walking towards Laurie's room in the sanitarium, the window on the door is yellow as if a light is on in the room. Then in the next shot it is blue as if a light was not on.
Continuity mistake: In one of the last scenes where Sara Moyer has a blanket around her shoulders. She has her palm pilot in her hand and she has just received a message from Berman saying that he can see her on the news. The very next second after reading that entry you can here the palm pilot shut so you know she a has closed it. Then the very next shot you can actually see her shut the palm pilot.