Revealing mistake: When Annie's body gets wheeled out of the house and her father closes her eyes, her lids blink even though she should be dead.
Continuity mistake: Jimmy walks across a huge puddle of blood before finding Mrs Alves dead on the stretcher. When he slips and is unconscious, you can't see any footprints, not even near the door where he came in.
Character mistake: The police claim the Myers house is at "45 Lampkin Lane." The address on the front porch clearly displays the number 709.
Continuity mistake: Dr. Loomis shoots out the passenger window of the marshal's car, but it seems to be intact in later scenes, like when the woman is outside using the radio calling for help.
Revealing mistake: When Janet spins the dead Dr. Mixter's chair around, you can see his right hand flinch.
Continuity mistake: At the very end of the first Halloween, Loomis' first shot hits Michael while he is struggling with Laurie. A few seconds later, he is staring down Loomis and breathing very heavily. At the beginning of Halloween II, the scene is reenacted to reflect the ending of the first movie, but here you cannot hear Michael breathing at all after being struck by Loomis' first shot.
Continuity mistake: After Jimmy slips in Ms. Alves' blood, his position changes between the side camera shot and the above camera shot.
Audio problem: When Michael bursts through the door at the hospital, Loomis fires his gun and Michael stabs him. He drops his gun on the floor and it makes no sound when it hits.
Factual error: At the end of the film where the blinded Michael is swinging his scalpel aimlessly, it makes loud "swooshing" sounds. This is pure fantasy. I have personally mimicked what Michael did using similar small scalpels and even larger knives without almost no sound when swinging them.
Continuity mistake: When Annie's dead body is rolled out on the stretcher her dad pulls the sheet back and revealing her slit throat. After a brief cut to him, when it cuts back to Annie the sheet covers her throat.
Continuity mistake: Notice how Michael is taking/reacting to being hit by the bullets at the conclusion of the first Halloween - you see him writhe in pain, his hand shake and grab near his side, and his body contort and literally twist before falling off the balcony - a believable shooting death scene. When the scene was re-enacted at the beginning of part II, all Michael does is lazily walk backwards and fall off.
Continuity mistake: When Loomis thinks he sees Michael but it is actually a drunk Ben Tramer in a mask, he runs after Tramer and pulls his gun. Brackett sees this and runs out of his patrol car, slams the door, and stops Loomis before Loomis gets off a shot. A few seconds later though, the car door is now open in the background.
Revealing mistake: When Doctor Loomis touches the blood in the beginning, you can see a bit of material (it appears to be plastic) sticking to his fingers as he pulls them up from the grass. It appears as though it was somehow involved in the effect of him touching the blood. (Perhaps to keep it from soaking into the ground?).
Plot hole: In the first scene Alice hears on the radio that three teenagers had been murdered in Haddonfield just down the street from where they live. Yet a few scenes later, the sheriff finds out from his deputy that 3 bodies have been found. Wouldn't the police department know that before it made its way onto the radio news?
Suggested correction: When Alice is on the phone, she tells her friend she can hear the sirens so the police knew about the bodies. As for the sheriff, he'd been busy with Loomis all night. He might have heard about the bodies in the house but figured the other policemen could handle it and that way he could continue helping Loomis. The main reason the deputy came to talk to him, however, was to tell him that his daughter was one of the victims found.
Halloween II was a troubled production, and the scene with Alice was added during re-shoots. Note that the previous scene with Mrs. Elrod also includes a news report about the discovery of the bodies. I've seen no concrete evidence of this, but I've wondered if the scene with Mrs. Elrod was shifted closer to the start of the film, and was originally meant to take place after the scene with the sheriff.
Good theory, but the deputy runs up to the sheriff and informs him for the first time of all three bodies.
Continuity mistake: When Michael stabs Nurse Jill in the back with the scalpel and lifts her off the ground, her shoes fall to the floor. A few seconds later, they are rearranged differently on the floor.
Continuity mistake: After the explosion and Michael is walking on fire, you'll notice he is right next to the burning stretcher. Then they cut to a scene of Laurie hiding behind a water fountain. In the next scene of Michael, he is now about 8 feet behind the stretcher walking towards her again.
Continuity mistake: Near the film's climax, the marshall is shown walking down a hallway by a soda machine and reacts to Laurie's screaming. He then makes a turn around to go see what was up. Several seconds (and many screams) later, Michael crashes through the door and the marshall is still running down the hallway by the same soda machine.
Continuity mistake: In the original film, the pumpkin at the Wallace's house was very small and fat, but in this film (which takes place the same night) you can see when all the cops and reporters are at the house that the pumpkin changed in size and the face is different as well.
Factual error: The films happenings are supposed to take place on Halloween of 1978, but the ambulance has rectangular headlights, which were not introduced on full-size Ford vans until the 1980 model year.
Other mistake: When Bud goes to check on how hot the water is, he rubs condensation off the gauges, but there wasn't anything on them to begin with.
