Continuity mistake: Laurie drops the items in the mail slot twice at the Myers' house. (00:58:30)
Continuity mistake: Laurie's hair changes from curly to straight frequently in the Myers' house.
Continuity mistake: Near the film's end, Myers crushes Dr. Loomis' skull with blood protruding from several parts of his face. In the following shot of him being dragged into the house dead, his face and head are perfectly fine.
Continuity mistake: When Laurie stops at the Myers house she has no backpack. She does in the next scene.
Continuity mistake: When Grizzly the truck driver stops at the truck stop, the attendant opens the hood and gets the hose twice.