At a personal appearance in North Hollywood, California, in the fall of 1999, Gary Busey discussed his experiences in making this film- including doing all his own stunts. In the film's ending, where he is thrown around the room, Busey said this was achieved by having him (off camera) run and jump on to an air-compressed catapult which would then launch him through the air and into various pieces of breakaway furniture. He sustained an actual injury in the part where he lands into the mirror due to the artificial glass. This is evidenced in the film where a piece is seen embedded into his arm (which bleeds) as he falls to the ground. He went on to say that his reaction of the werewolf breaking through the wall was genuine as there was no rehearsal of that scene and it was completed in a single take.
Producer Dino De Laurentiis was very unhappy with the werewolf used in the film. He was disappointed in both the way it looked and the way the costumed actor moved. This proved to be a bit of an insult to the actor wearing the suit as he was an accomplished modern dancer and was hired specifically for his movement skills.
The werewolf dream sequence utilized a total of seventy extras that were divided up into four groups with various levels of make-up and costume. These ranged from approximately ten principal actors used for close-ups and action shots, having the most refined looks, while the remainders were just made to appear menacing and fill up the rest of the church to give it a full house appearance.
Complete construction of the werewolf costume took three months. After finalization of the shape and design, using three-dimensional clay heads, the entire costume was made of foam and polyurethane and was covered with actual bear hair. The head of the costume was mechanically operated by six people from a distance of up to thirty feet away.
The Coslaw residence was an actual home used in Wilmington, North Carolina. Though the interiors were a set on a sound stage, the actual home itself was relocated in the 1990s to another area in town due to a massive shopping center that was built in it's place.
Tarker's Mill, when the action takes place, is a fictional town within the Stephen King universe. It borders locations of other King's works also adapted to film, such as Chester's Mill (Under the Dome), Derry (It) and Castle Rock (Needful Things, Cujo and Pet Semetary), among others.
Stephen King asked that the werewolf be ambiguous, plain, and hard to see, in contrast to the hulking monsters seen in other werewolf films and books in the early-to-mid-1980s, with the end result being a creature which looked more like a black bear than anything else and did not really have any identifying characteristics. After seeing Carlo Rambaldi's design, per King's request, producer Dino de Laurentiis was very unhappy and demanded a change, which both King and Rambaldi refused. Eventually pre-production fell behind schedule and director Don Coscarelli opted to start filming the non-werewolf scenes without knowing what would happen with the werewolf suit. After completing the non-werewolf scenes and not having any clear picture about what would happen with the film Coscarelli resigned as director and was replaced with Attias. When pressured to either cancel the film or accept the design de Laurentiis relented and allowed filming to continue with Rambaldi's werewolf suit. A modern dance actor was hired to perform the stunts inside the suit but de Laurentiis was also unhappy with his performance and demanded a change. As a result, Everett McGill, who played Revered Lester Lowe in human form, wound up acting out most of the scenes in the werewolf suit and was credited with a dual role.
The fireworks on the bridge scenes were filmed on two separate occasions, months apart. After principal photography was completed, in the fall of 1984, they discovered a continuity problem. The wide shots and close-ups of Marty lighting the fireworks didn't match. They returned four months later to re-do these scenes, and by then (due to the seasonal change) much of the foliage and trees had lost their leaves. Great lengths were taken in the close pick-up shots not to show this in the background.
Differences between the novel and movie include: *the fact that in the novella the murders start in January and end in December, spanning almost a full year. In the film, the murders start in the Spring and end on Halloween. Additionally, the murders in the novel each coincide with a specific holiday that month i.e. New Years Day, St. Valentines Day, April Fool's Day, etc. No such importance is given to the murders in the film. Arnie Westrum is killed in the Spring of 1976, presumably May (Jane's voice-over mentions that school is about to let out). In the novella he is killed on New Years Day. *Stella Randolph is killed by the werewolf in order to prevent her from committing suicide. In the novella the character is a virginal seamstress who seems to be suffering from delusions. She sees the werewolf watching her from outside her window on Valentines Day and lets it in, imagining that it is her secret lover come to visit her. The werewolf promptly pounces on her and kills her in her bed. *In between Stella and Brady Kincaid's deaths, in the novella a drifter is killed in March while passing through Tarker's Mill. Wolf prints are found near his corpse. His death is completely omitted from the film. *In between Brady and Owen Knopfler/the vigilantes' deaths, Clyde Corliss, a janitor at Reverend Lowe's church, is found disemboweled on the church's altar. His death is completely omitted from the film. *As stated above, Owen Knopfler is named Alfie Knopfler in the novella. He owns and runs the town diner, and is killed after High School Graduation in June in his diner. He sees a patron (later revealed to be Reverend Lowe) transform into the werewolf in front of him before he's killed. *In the film a vigilante mob goes after the then-unknown killer in the woods. In the novella, there is reference to a vigilante group heading out to the woods, but Reverend Lowe drives to Portland, Maine in order to avoid them (and instead runs into Milt Sturmfuller). *While Sheriff Haller is killed confronting Reverend Lowe in his garage, Constable Neary is killed in August while drinking in his parked truck. He has his face ripped off by the werewolf and is devoured shortly afterwards (similarly to the vigilante who has his face ripped off in the woods in the film). *Milt Sturmfuller in the film is killed while investigating strange noises in his shed. In the novella, it is revealed that Strumfuller is a wife-beater (a point that is merely implied in the film). He leaves for Portland, Maine in December to meet his mistress and is confronted by the werewolf, who decapitates him. Unlike the film, in the novella Sturmfuller is not considered to be one of the murder victims by the town since he was killed in another vicinity. *Elmer Zinneman inadvertently saves Marty from Reverend Lowe in the film when Marty calls out to him while trapped in the covered bridge. In the novella Zinneman is a local farmer who hears a commotion on his farm one night and decides to investigate with his rifle. He hears a bloodcurdling wolf howl and cowers in his house with his wife. The following morning he finds that his pigs have been slaughtered, with wolf tracks all around the pen. His brother-in-law tells him that it's obvious that a werewolf was responsible, and that the residents of Tarker's Mill are in denial because he lives two counties over and they all know what it is. *On Halloween, Red, Marty and Jane confront the werewolf. In the novella, Marty goes trick-or-treating on Halloween in search of the werewolf's identity and is shocked when he sees Reverend Lowe wearing an eyepatch (it is explained that the Coslaws are devout Catholics and that Lowe is a Baptist; as a result Marty never runs into Lowe until nearly 4 months later since they worship at different churches). *In the film, Marty shoots out the werewolf's eye with a firework in October, when the town fair and fireworks are canceled. In the novella, the maiming occurs on Independence Day. *In the film, Reverend Lowe knows that it was Marty who injured him in his werewolf form. In the novella, Lowe does not remember what happens when he transforms; all he knows is that he wakes up the following morning with scratches and bruises on his body, and with crusted blood on his lips and fingernails. As a result, when Marty injures him (in werewolf form), he awakens the following morning with his eye blown out but with no recollection about how it occurred. *Marty sends Reverend Lowe anonymous letters indicating that he knows who and what he is, and that he (Lowe) should commit suicide in order to stop killing people. In the film, despite the anonymous nature of the letters, Lowe knows that Marty is responsible; in the novella, Lowe decides to go into town and listen to gossip in order to find out who was attacked on July 4 (the day his eye was blown out). Marty signs the last letter with his name, letting Lowe know who was responsible for his maiming.
Both Everett McGill and Gary Busey would eventually come to their demise at the hands of Casey Ryback played by Steven Segal in Under Siege and McGill in Under Siege 2: Dark Territory. Busey in a submarine that blows up in Under Siege and McGill on a train kitchen in Under Siege 2.