5. Dan Aykroyd’s script originally took place in the future, but Harold Ramis rewrote it to take place in modern times.
As a result, the production budget was cut from a projected $300 million (according to director Ivan Reitman) to just over $30 million.
15. The term “proton pack” was never actually used until the middle of Ghostbusters II.
In the sequel, Spengler said “before we go any further I think we should get our proton packs.”
17. The film was originally titled Ghost Smashers.
But director Ivan Reitman called it “the telephone book” because of how long the first draft was.