Corrected entry: At the end of the film, Sheriff Meeker has captured Michael and we see a shot of him sitting in his jail cell, with his mask still on. Even putting aside suspension of disbelief that this is a horror film, it almost goes with certainty that no-one, least of all Michael, would be allowed to be processed in a jail, and then be in a cell, wearing his patented mask - all of that stuff would have been confiscated. Michael of all people would have never been given a special privilege like that, even if his face was deformed.
Corrected entry: When Michael sticks the pitchfork through Spitz, he was on top of his girlfriend. Shots afterwards of Spitz show puncture wounds that went clear through his stomach, theoretically his g/f would have been harmed by this (especially considering the positioning of both of their bodies), but she wasn't. And no argument can be made that the pitchfork's blades weren't long enough, since they were probably over 12" long a piece.
Corrected entry: During the scene where Dr. Loomis is at the police station, he tells Sheriff Meeker to look at his burned face and says to him, "this is what I endured 12 years ago (Halloween in 1978)." Now remember, the events of Halloween 5 take place on October 31, 1989, and a year earlier (Halloween 4), Michael came back looking for Jaime on October 31, 1988. Lastly, after being shot at the end of Halloween 4, we know Michael was taken in by some fisherman for exactly one year, that was explained at the beginning of Halloween 5. Therefor, Dr. Loomis should have said 11 years ago, not 12.
Corrected entry: The Halloween movies are set in Illinois. When the teens are at the party, they are talking about how some of them were going skinnydipping (even though we never see this scene). Even if it was set in southern Illinois, there would be no way anyone could swim outdoors on October 31. The water would be far too cold. Especially at night and especially while naked.
Corrected entry: Myers chases Jamie around the farm & tries to run her down with a car. Yet this little girl is able to outrun the car for about 5 minutes of screen time.
Corrected entry: When Jamie first climbs into the lauundry chute there is a door directly to the right of the opening. (Michael has to decide whether to go through the door or check the chute) But when she climbs up out of the chute there is no door.