Trivia: Director Jason Reitman is the son of Ivan Reitman, director of the original "Ghostbusters" and "Ghostbusters II." As a child, Jason actually had a cameo in "Ghostbusters II" during the birthday party in the beginning. (He's the kid who tells Ray he heard the Ghostbusters were "full of crap").
Trivia: Part of the reason a third "Ghostbusters" movie wasn't made in the 90's or 2000's was because Bill Murray didn't really want to return to his role of Peter Venkman. It was even rumored that Murray would immediately shred any "Ghostbusters 3" scripts that were sent to him. After many months of speculation, it was finally reported that Murray agreed to reprise the role in this film, alongside many other original cast members.
Trivia: Originally, sequels were planned for the 2016 "Ghostbusters" reboot. However, when the film attracted some controversy and fell short at the box office, plans for the sequels were abandoned. Eventually, an idea was hatched for a direct sequel to the original two films, which became "Ghostbusters: Afterlife."
Trivia: The giant eyeball ghost was modeled after a toy that was released for the 1987 cartoon.
Trivia: SOME SPOILERS: Harold Ramis' daughter Violet got to visit the production a few times, and was even able to try on her father's original proton pack, which was being kept in storage. She has greatly praised the movie and the effects used to add her father into the film as a ghost, and feels he would have definitely approved of it.