When Mrs. Strode is cleaning up her porch she is wearing Nike Air shoes. When she goes into the house, into the basement we see a close-up of her shoes and they've changed completely; to Saucony brand shoes. When she discovers Michael in her house whilst on the telephone, she is wearing the Saucony sneakers, then as she runs into her yard, once out of the house the Nike Air shoes reappear.
When he is on the phone with Barry Simms, Tommy manages to hold the phone in his right hand and, at the same, time type with the same hand.
If the map in the bus station were to be believed, Haddonfield is located in Livingston County, Illinois. In the previous films, it was in Warren County.
There is blood running down Jamie's chin when she is being impaled on the farm equipment, but then it disappears and reappears.
Michael appears to lose and gain weight in various scenes.
When Kara calls home, Beth answers a cordless phone, but the base station would not work without electricity.
Blood begins to coagulate within minutes, but Tommy finds Jamie's wet blood in the phone booth and in the bathroom sink. These small amounts would have already dried.
(at around 6 mins) The text of the newspaper cuttings on Tommy's wall do not relate to the events of the original Halloween. While the headlines refer to Michael's killings, the body of the articles discuss, amongst other subjects, an international conference and political difficulties for a city mayor.
When the pair is found murdered in bed, you can see the girl's eyes moving.
In Halloween 5: The Revenge of Michael Myers, it was shown that Michael and the Man in Black had identical Thorn tattoos on their wrists. In this movie, Dr. Wynn was revealed to be the Man in Black. Since he and Dr. Looms were longtime colleagues, it seems odd that Loomis wouldn't have previously noticed the Thorn tattoo on Wynn's wrist.
All of the newspaper clippings in Tommy's room look brand new and not yellowed by age despite being up to 17 years old.
When John Strode is in the basement and Michael stabs him,at first he stabs him it's at or below his waistline towards the side. The camera changes and the same stab is now almost dead center of his chest.
John Strode was the only member of the family who knew that they were living in Michael Myers' old house. Considering that Michael's story was well known in Haddonfield, the rest of the Strode family should have realized this.
During the flashback scene at the beginning of the film when Jamie is being taken by the man in black away from the police station, she is forced into a mid 1990's model Ford conversion van. Since the scene took place in 1989, this model wouldn't have existed, as the Ford vans that were built during the 1980s had rectangular-shaped grilles instead of the trapezoidal-shaped one that was shown. (Producer's Cut).
@00:26:00 Tommy listens to the recorded radio show on a Revox tape-deck.
Rewinds the tape to hear a section again.
The tape speed drops from 15ips to 7.5Ips without changing the pitch.
Its clearly to see a slower reel speed.
In the Theatrical version, before Michael starts the doctor massacre, he hears the sound of Tommy and Kara fleeing into another room. He stops, and turns around to investigate the sound but doesn't find anything. As he turns to walk the other way, they show his reflection in mirrors on the wall, and if you look, you'll see a crew member in the mirror just before the mirror is out of frame.
In Halloween (1978), Dr. Wynn tells Dr. Loomis that Haddonfield is 150 miles away from Smith's Grove Santitarium. The map in the bus station shows that Haddonfield and Smith's Grove are located between Pontiac and Dwight, IL, respectively. Pontiac and Dwight are only about 20 miles apart in real life.
When Tommy is listening to Jamie talk to Barry Simms again he could hear the Bus Station attendant announcing a bus departure, but during the actual scene when it is happening there is no such announcement.
At the beginning of the movie when Barry Sims show is on the radio, he says Haddonfield banned Halloween but, children are seen trick or treating.
Despite being depicted as an expert on The Cult of Thorn, Tommy mispronounces "Samhain," pronouncing it phonetically as SAM-hane. As a Gaelic word, its pronunciation is closer to "SAH-win" or "SOW-in."
Tommy's narration at the beginning states that after Michael escaped from Smith's Grove "One by one he killed his entire family until his nine-year-old niece Jamie Lloyd was the only one left alive." In fact, Michael did not kill any of his family members after escaping. His only relative besides Jamie was his sister Laurie Strode, who died in a car accident between movies.