Trivia: Jarred Blancard, who played young Henry Bowers, was very much the polar opposite of his savage character. For example, he absolutely hated having to call his co-star Marlon Taylor the "n-word," and was very uncomfortable saying it. He would frequently and profusely apologize to Taylor before and after every take when he had to say.
Trivia: When the adults walk into the library, you'll see some of Bill's books on display (Bill is described as the Stephen King character), and all of Bill's books (Whether it's the name, topic, or cover picture) are based in some way on Stephen King's books. For instance - The Glowing/The Shining.
Trivia: At the library IT writes something on the type-writer, a verse which Bill tells the others his mother gave him as a kid to help with his stuttering. The verse goes "He thrusts his fists against the posts and still insists he sees the ghosts." In the book, young Bill used this verse to defeat IT in the Chüd ritual.
Suggested correction: In the book they don't find out about the ritual until they are adults. Adult Mike is the one who told them about it after years of research.
Trivia: Henry Bowers shares his name with Robert Scott's companion during the race to the South Pole.
Trivia: The children call themselves the Lucky Seven. Seven is known in fairy tales to be a lucky number.
Trivia: In the scene where IT appears as Belch to convince Henry Bowers to escape from the asylum, Henry says "they have Koontz watching the door, Koontz is the worst, I hate him". One of Stephen King's rival authors is Dean Koontz.
Trivia: Director and co-writer Tommy Lee Wallace reportedly hadn't read the book when he made the mini-series. He based his writing and direction around the pre-existing work of Lawrence Cohen, who had written earlier drafts of the series. Wallace felt that the film should stand on its own, and thus he didn't feel the need to read the book at the time. He has since read the book and admitted he felt the mini-series fell a little short as an adaptation.
Trivia: The mini-series was originally going to be directed by "Night of the Living Dead" director George A. Romero, who intended for it to be ten hours long. Romero had to bow out, and the mini-series was substantially edited down to a more palatable and cheaper four hours. (With commercials).
Trivia: Co-star John Ritter was a huge Stephen King fan, and was reportedly a little miffed that the "turtle" from the original novel was not referenced in the movie.
Trivia: Seth Green is terrorized by a werewolf in the film. He would later go on to play a werewolf in the cult-favorite series "Buffy the Vampire Slayer."
Trivia: The film debuted in 1990. Actor Bill Skarsgard, who would later go on to portray Pennywise the clown in the 2017 reboot, was born the same year.