What Could Have Been: This image◊ was created in case Jason Todd was voted to survive A Death in the Family. A very similar colored version (here◊) was printed in Batman Annual 25, which recounts Jason Todd's resurrection, as well as the reality-warping that caused it.
Awesome, Dear Boy: The reason several of the guest-stars took the gig as villains. Victor Buono as King Tut is the best example: he was a huge (no pun intended) fan of the comics, and was so into the series he made more appearances than any other guest-star outside of Newmar, Romero, Meredith, and Gorshin.
Fake Brit: Lord Ffogg was played by Rudy Vallee, an American born in Vermont.
Spencer Tracy was offered the role of The Penguin, but would accept only on the condition that the series got to end with him killing Batman.
Also, Two-Face was once considered as a villain for the show, only his origin would be that he was a TV news anchor who had a TV set blow up in his face. Clint Eastwood was even considered for the role but the character was ultimately dropped because he was considered "too gruesome" for such a light-hearted show.
The season 2 episode "The Puzzles Keep Coming/The Duo is Slumming" was originally written for the Riddler, but with Frank Gorshin having contract disputes with the producers, the similar Puzzler was created instead.
Tim Burton once said of the film "I liked parts of it, but the whole movie is mainly boring to me. It's OK, but it was more of a cultural phenomenon than a great movie." He also wasn't horribly enthusiastic about how Prince's songs were used in the film.
Main screenwriter Sam Hamm, one of the many writers who worked on the script, has also absolved himself from the sequence where Alfred leads Vicki to the Batcave, a move that didn't sit well with a lot of fans. Hamm said the scene didn't come from him and that the day Alfred let someone in the Batcave would be his last day of employment. It gets a Call Back in Returns.
In the original script, written by Tom Mankiewicz, crime boss Rupert Thorne hires Joe Chill to murder Thomas Wayne because he is running against Thorne for city council.
A later draft written by Sam Hamm also has a large part of the film concentrating on Bruce traveling abroad and training with Henri Ducard, whom Bruce would later discover to be a film. This script was later overhauled into the version seen in the film, and Ducard was deleted. Months before the film's release, then-DC Comics editor Denny O'Neil asked Hamm to guest-write a "Blind Justice" storyarc throughout Batman-themed comics as a tie-in, and Hamm introduced his character there (specifically, in Detective Comics #599, April 1989). Ducard would later appear, played by Liam Neeson, as a Composite Character with Ra's al Ghul in Batman Begins.
Burton stated in an interview that he had initially wanted Adam West and Julie Newmar, from the 1960s series, to play Thomas and Martha Wayne in the flashback. Audiences would recognize West and Newmar from the series and see them get shot, symbolizing the "death" of the old Batman. Script rewrites caused this to be scrapped, and West later said he wasn't even offered the role (and even if he was, he wouldn't have taken it).