This was actor Jack Albertson's final theatrical film (although he filmed another made-for-TV movie the same year he died). In poor health and suffering from cancer all through filming, Albertson passed away a few months after this movie's release. He nonetheless lived long enough to see it at it's world premier in Hollywood, in which he attended in a wheelchair with an oxygen tank and mask.
During filming Gary Sherman purposely avoided letting the color red be visible in any scene, so the sight of blood during the murder sequences would be all the more shocking. Sherman even went as far as to have the tail lights of cars replaced with purple lights, instead of the normal red.
Melody Anderson's reactions to being shot were very authentic. One of the squibs set to explode under her dress actually flew upward very close to her ear and gave her a scare, it also caused her to lose hearing in her right ear for a few moments.
Director Gary Sherman intentionally chose foggy weather conditions to film in while on location in California. The films setting is suppose to be Maine and the locations looked most like northern New England when the weather was foggy. In addition Sherman liked the ominous mood the gloomy weather created.
On the day when the opening beach scene between Freddie and Lisa was shot, the weather conditions were too beautiful for director Sherman's liking. The crew constructed a huge flag to hang from a rigging on a cliff overhanging the beach to block most of the sunlight out so the scene could be shot with the films dim atmosphere.
The films plot was re-edited numerous times throughout the production. Originally the attack on the family occurred later in the film, after the hitchhikers murder, which is why the resurrected hitchhiker can be seen among the attackers during the scene with the traveling family in the old house.
Due to child labor laws, the filmmakers could not get permission to use the boys who played Jamie at night. Because the kids' entire part took place at night, a huge tent was constructed that completely covered the family car and the haunted house, making it look like it was nighttime underneath it. To properly ventilate inside the tent so that the cast and crew could breathe, fans were set up. But they made so much noise that the live sound that was recorded during filming was unusable. So all of these scenes had to be dubbed by the actors in post-production. This is why Nancy Locke's mouth is frequently moving when she's not talking.
The effects team who created the "dissolving head" effect for Doc's murder mentioned in an interview that the director had originally told them that he wanted to do the scene in one unbroken shot, meaning they had to build a head that was both convincing and also would "melt" the way they wanted it to. They lamented the fact that, while they did the best they could with what they had, the director ended up using a cutaway shot anyway, which would have given them the opportunity to make the scene much more realistic.
Stan Winston's special effects went beyond creating gore for the film. The figure in the full body cast lying in George LeMoyne's hospital bed was a mechanical dummy built by Winston. The life-like detail and elaborate movements the dummy was rigged to make gives the appearance that its a real person and makes the infamous needle-eye stab all the more startling.
The film suffered a lot of interference from PSO International, the third financer who bought out the second financer, Aspen (who in turn had bought Guinness, the original financer). PSO wanted to emphasize gore over comedy, the latter of which Gary Sherman's directors' cut had concentrated on. As a result, numerous scenes were cut or shortened, and two scenes of graphic violence were tacked on at PSO's request: the killing of the drunk fisherman (Ed Bakey) and the acid death of Doc (Joe Medalis). The death of the fisherman (which was originally an off-screen kill in the first cut) was done by Stan Winston, but they could not get Winston back to off the doctor (which was not in the first cut at all, as he was supposed to be dead already), so another FX team was used on that one sub-par effect.
The scene where Janet comes home and speaks to Dan briefly was done in one long, elaborate tracking shot. The shot began with a gigging that attached the front door of the Gillis house to the camera. The camera captures Janet pulling up, pulls back as she approaches, and the crew quickly bolts the door in the door frame (detaching it from the camera rigging). The shot then continues to pull back revealing the door as Janet opens it, then follows her as she enters the living room and speaks to Dan. Then it was suppose to continue to a front window where we would see Janet leave again (though this bit was cut from the film).