Continuity mistake: Rachel throws a couple of suitcases and Jamie throws 2 more and a sleeping bag down the stairs. Next shot shows a chair and boxes that were never thrown. (01:08:10)
Other mistake: In the scene where Jamie is in the closet, looking at a photo of her mother (Jamie Lee Curtis). The photo looks exactly like the scene where Laurie is sitting waiting for Annie on the ledge in the original Halloween, which wasn't photographed at the time, it's clearly a still from the movie.
Revealing mistake: When the guys are driving down the road, you can see Michael isn't under the truck. Yet 2 minutes later, he climbs in the bed. (01:16:25 - 01:18:10)
Character mistake: As we know throughout this movie series, Michael's middle name is Audrey. However when the doctor is typing Michael's release form, he types his middle initial as "M".
Suggested correction: Michael's middle name is only mentioned in an additional scene that was added to the television version of the original Halloween. If going by the theatrical versions Michael's middle name was never known, so not really a mistake.
Doctors at a sanatorium would certainly know Michael's middle name. It's been on file for decades.
Continuity mistake: When Dr. Loomis is thrown through the window by Michael Myers in the school notice that Myers' hair has strangely turned white. The next scene Myers' hair has gone back to being brown. This is more evident in the widescreen version. This is because during the hectic shoot, an unfinished mask that wasn't painted or dyed yet was accidentally grabbed by a crew member for that one shot. It wasn't caught until the film was being edited. (01:13:50)
Continuity mistake: Myers at the end rips Rachel's shirt on the sleeve when she is driving the truck, right after he rips it, it is together again, he rips it again, then it is together again.
Continuity mistake: Rachel dumps a cup of coffee on Sheriff Meeker's daughter's white T-shirt in the kitchen yet there's no sign of a stain. It's not even wet.
Plot hole: When the deputy arrives at the sheriff's house, Michael gets out and leaves the door open. The deputy comes out to the car and sees it open. And he thinks nothing of it, despite knowing he didn't open it. Logic would say, "Well someone else opened it."
Continuity mistake: Pay close attention to the scene at the end of the movie when Sheriff Meeker and several other troopers start shooting Michael. As the shots are being fired by multiple men, you will notice one of the troopers on the far left side of screen (blue/white flannel shirt, beard) lighting a stick of dynamite. As the shots pan back and forth between the troopers firing their shots and the shots hitting Michael, you will see this same trooper continue to keep lighting the dynamite. A few seconds later in the sequence while more shots are being fired at Michael, you will now see that same trooper now suddenly holding (and about to put down) a shotgun, the dynamite is now nowhere in sight.
Revealing mistake: When Michael sticks his thumb in the ambulance guy's head, you can see the inside of the fake hand.
Plot hole: Near the end of the movie, Jamie and Rachel are being taken down the highway to safety by the vigilantes when Michael climbs into the back of the truck from being underneath it. Michael then struggles, stabs, and violently throws two of the vigilantes from the truck, and the third vigilante, standing only inches from the other two and still holding guard in the back of the truck, appears to see or hear none of the commotion. Impossible, even for horror films.
Visible crew/equipment: When Loomis looks out the window for Michael, you can clearly see the cameraman's reflection (best seen on the Limited Edition DVD).
Audio problem: When the head of the Federal Sanitarium gives over control of Michael to the Doctors from Smith's Grove, he says, "I can safely say that Michael Myers is in your hands." If you watch his lips, you can see that the sound of the words and his lip movement is way out of sync.
Continuity mistake: In the trick or treat scene, Rachel's purse disappears then reappears when she runs from Michael.
Plot hole: At the end of Halloween 2 Michael is completely engulfed in fire for several minutes. Even if somehow he was to survive he would be covered in scars. When we see him at the beginning of part 4 he has a few small scars on his arms. Same with Loomis, he has a few small scars on his arms and one on his cheek despite being in a gigantic explosion and fire. Obviously this was done so they could bring the 2 characters back but it still makes no logical sense.
Suggested correction: Michael has the supernatural ability to heal as shown when he's shot in the eyes at the end of Halloween 2 because in this one he can see, as for Loomis it's possible he was blown into another room or into an area into the room where the flames couldn't reach him, no mistake.
Michael does have some scars though. If the excuse that he heals is the reason he doesn't have more than all of them would be healed after 10 years. Also Loomis was in the same room with Michael, even if Loomis was blown into another room he would have been engulfed in flames and would have been either dead from the shock wave or still burned worse than he is in part 4.
Suggested correction: This one's tough. On the one hand, this is intentional and if it were released today I'd chalk it up to being a (very) soft continuity reboot and that in this film the explosion was simply not as severe as it was in Halloween II. On the other hand, in the context of its release era, and just by watching you can sort of tell they were hoping viewers either had a fuzzy memory of Halloween II or were willing to just go with it. I think I'll err on the side of the former, but it's interesting.
The original script contained an opening scene which showed how Dr Loomis was blown out of the hospital. They had no enough money, so that scene was never shot.
Plot hole: At the end of Halloween II Dr Loomis blows up the room. Since he was inside the room when it blew up in flames, how did it not kill him? And that bad of a fire only scarred one side of his face and one arm and hand?
Visible crew/equipment: When Dr. Loomis arrives to the gas station the boom mic's shadow is visible on the ground. (00:19:02)
Other mistake: When Doctor Loomis encounters Michael in the gas station the camera zooms in on Michael standing directly in the kitchen and Loomis shoots at him, but when he takes a closer look he is totally surprised Michael vanished when he saw him.
Continuity mistake: When Jamie backs up into Michael in the drug store his hands are at his sides.Yet when she looks up at him he's putting on his mask.
Plot hole: Toward the end, when Jamie and Rachel are being taken to safety by the vigilantes, Michael suddenly climbs over the back of the truck and slays all the guys one by one. There is no way he could have been 'hiding' under the truck as he was still deep inside the school when the truck sped out of the lot and down the road. Obviously added for dramatic effect at the end.
