Trivia: The post-production process of the film was very dramatic. The studios became worried that the subject matter was too strange for audiences, and in an attempt to make the film faster and simpler to understand, they demanded that nearly an hour of material be removed from the film. Director Clive Barker also maintains that the film wasn't marketed properly. A Director's Cut of the film (containing much of the cut footage) was announced more than 20 years after the film's original release-date.
Trivia: Even though the characters themselves are constantly confused as to which of them is Rosencrantz and which is Guildenstern, there is a way for the audience to make sure: In the scenes where they take part in "Hamlet" and interact with others, Gary Oldman always delivers the lines of Rosencrantz, and Tim Roth always delivers Guildenstern's.
Trivia: Director William Peter Blatty wanted to title the film "Legion" after his novel the script was based on, while the studio (understandably) wanted to call it "The Exorcist III" for brand-recognition reasons. Blatty absolutely hated "Exorcist II: The Heretic" and felt that the title "The Exorcist III" would suggest this movie followed that one, so he countered by suggesting they title the film "The Exorcist 1990." The studio eventually won out and went with "The Exorcist III."
Trivia: When the agent pulls from the computer record Richard's file, an alias listed is "David Putnam - Columbia Pictures", employed from 06/04/1973 to 02/01/1975. That's an obvious reference to producer David Puttnam (two Ts), who had a brief stint as head of Columbia Pictures in 1986-87, not making many friends in the then Coca-Cola owned production company. (00:12:50)
Trivia: Ellen Robertson's dog is named Hercules. Hercules was the name of Arnold Schwarzenegger's character in his first movie, and Arnold also starred with Linda Hamilton (who played Ellen Robertson/Burrows) in The Terminator and Terminator 2. This was done again in Terminator 3: Rise of The Machines which had a scene with a cat named Hercules. (01:02:50 - 01:11:25)