Trivia: Rene Russo was originally cast to play criminal psychologist Dr. Chase Meridian when Michael Keaton was still attached to the project as Batman. However, when Keaton dropped out of the project and was replaced by Val Kilmer, Russo was deemed too old to play his love interest and was replaced by Nicole Kidman.
Trivia: In the original Batman (1989), Harvey Dent was played by Billy Dee Williams. Williams accepted the role with the knowledge and expectation that Dent would eventually become Two-Face. Williams had a clause in his contract reserving that role in any sequels for him. Warner Bros. had to buy out his contract so that they could cast Tommy Lee Jones.
Trivia: When Edward Nygma is deciding what name to give himself, one of the names he chooses is "The Puzzler." The Puzzler was a named used by two different DC characters who both became criminals.