Audio problem: Michael tears Rachel's sweater. The problem is it's not actually being torn, just sounding like it is. (01:19:50)
Continuity mistake: When the sheriff's daughter is killed she goes from wearing a T-shirt to a flannel shirt.
Suggested correction: She changed her clothes because Rachel poured coffee on her T-shirt in a previous scene.
Continuity mistake: When Michael throws Dr. Loomis out the window at the school, the next shot shows him being thrown through a glass door.
Revealing mistake: Dr. Loomis fills his tank, and when the camera changes it is not Donald Pleasance. (00:18:30)