Trivia: The production of the film was notoriously troubled. There were numerous writers working on numerous drafts of the script before one was finally settled on. Filming was hectic with many scenes being omitted or re-written on-set. And after the first cut was complete, a poor test-screening lead to the film going through drastic reshoots that altered much of the story, including the addition of a brand new ending, which had to be written around the fact that co-star Donald Pleasance passed away shortly after the end of principal photography.
Trivia: The original version of the film that was created before the plethora of reshoots (known as the "Producer's Cut"), was a famous and infamous "legend" among fans. For many years, it was only available illegally and in generally poor condition through bootleg copies that were sold at conventions and festivals, although it eventually found its way online. It wasn't until 19 years after the theatrical cut debuted that the Producer's Cut was given any sort-of official release, when it was included in a Limited Edition Blu-Ray boxed set of the series. It has since also been given a stand-alone release on Blu-Ray.
Trivia: The film went through several titles during production, and the final title wasn't settled on until shortly before the film was released. An early trailer even referred to the film by an alternative title: "Halloween 666: The Origin of Michael Myers", which itself was a combination of titles from two different drafts of the script.