Moustapha Akkad has said that one of his biggest regrets about the film was killing off the character of Rachel Carruthers. In retrospect, he would've kept her alive, but she was killed in an attempt to show that no one, not even Rachel, was safe from Michael.
In the infamous laundry chute scene, Jamie was originally stabbed in the leg but the shot was cut from the film by the MPAA because it was deemed "too disturbing". Danielle Harris still owns the prosthetic leg.
Don Shanks revealed in an interview that many of the scenes involving the man in black had him playing the character, because of speculation that he was a blood relative of Michael Myers. He also admitted that even the writers had not yet decided the man in black's identity.
As part of the opening, an alternate scene was shot but never used. The scene shows a man who finds Michael Myers body at the beginning and removes his mask, staring at it weirdly. The filming of it can be seen in the documentary, "Inside Halloween 5".
KNB Effects had designed grotesque facial makeup for Michael Myers' unmasking towards the end of the film. The producers told them to do so as an option, either showing Michael's badly scarred face or keep it in the dark. They went for the latter.
In terms of his appearance, the Man In Black's wardrobe of a long, black coat and black cowboy boots, is a nod to country music singer Johnny Cash, who often wore long, black coats and black cowboy boots, thus earning him his famous nickname "The Man In Black".
When filming a scene, Donald Pleasence accidentally hit Don Shanks in the nose, breaking it. As a result, they had to cut out the nose of the mask and add on a paper thin nose cut off of another H5 mask. The edges of the nose appliance can be seen clearly in a lot of the film.
The scene where Michael Myers drives a car while wearing a different kind of mask was initially scripted to have him wear a Ronald Reagan mask. However, the idea of a Reagan mask was soon rejected in order to keep the film devoid of any political subtexts.
This film had one of lowest international theatrical distributions of the series, being seen only in Argentina, Columbia, France, Germany and Turkey. Elsewhere, it was released straight to video, with large campaigns in Norway, the UK and Spain.
The film had been fighting an X rating with the violence, blood, and gore. Some scenes were trimmed down to keep it rated R, including a shot of Mike quivering on the ground after Michael stabs him in the head with a hammer claw, a shot of glass embedded in Officer Eddy's face after Michael punches through the windshield, and Billy's leg being hit by the Camaro.
This is the first Halloween film to have Michael Myers with black hair. His original hair color is blonde. You can see Michael in this film without the mask twice, first when he wakes up in the cabin and again in the attic when he's in front of Jamie. Tom Morga is one of two actors to have played Myers who had a different hair color. The other is Brad Loree in Halloween: Resurrection (2002).
Tina was originally scripted to wear a devil costume to the Halloween party but this was changed so that Samantha wore this instead as Dominique Othenin-Girard did not want the heroine dressed like a devil.
The laundry chute scene was filmed with 30 different sections of the laundry chute. Some were full props, others were positioned horizontally to run the camera through on a dolly, and others were various sections that had cut-out portions for filming. Although the scene was very complex, it was all shot in one night.
The Jamie Lloyd character has a striking parallel to the Tommy Jarvis character from the Friday the 13th series. Both characters appeared in the fourth, fifth and sixth films of their respective series. They were both about the same age in their first appearance. They both become institutionalized and develop homicidal tendencies themselves after the killer. In this film, Jamie starts out as a mute. In the fifth Friday the 13th, Tommy rarely speaks. At the end of that film, Tommy is seen holding a knife and essentially becomes Jason. At the end of the previous Halloween, Jamie is seen holding a pair of scissors and she essentially becomes Michael.
In an article that appeared in the October 1989 issue of Fangoria magazine, director Dominique Othenin-Girard claimed that the film's ending was not scripted. Donald Pleasence stated in the same article that the film would contain the death of his character Dr. Sam Loomis.
When Rachel's death scene was altered by the actress' request, it was changed in order to reflect the flashback where Jamie stabbed her foster mother in Halloween 4: The Return of Michael Myers (1988) in a similar fashion.