Most of the scenes with Batgirl were cut, because Alicia Silverstone had gained a few pounds during production and the wardrobe team had to refit her costume. When the press discovered the news, they slammed Silverstone's weight gain and mocked the actress for being "too fat" to fit into her costume. Director Joel Schumacher publicly defended Silverstone during interviews and press meetings, joking "What is this girl's big sin - that she ate some pizza?" When the taunting continued, Schumacher lashed out at the reporters that taunted her. He said in a magazine interview, "It was horrible. I thought it was very cruel. She was a teenager who gained a few pounds - like all of us do at certain times. I would confront female journalists and I'd say, 'With so many young people suffering from anorexia and bulimia, why are you crucifying this girl?'"
In later interviews, director Joel Schumacher blamed studio pressure to make the film more "toyetic" (i.e., a showcase for marketable toys and games). In a "making-of" documentary on the DVD, he apologized to disappointed fans.
Mr. Freeze says 27 "ice puns" throughout the movie.
Before filming began Arnold Schwarzenegger had heart surgery. Studios were aware that Arnold Schwarzenegger had developed a heart condition and were reluctant to insure him for an action movie, so he had open heart surgery shortly after being cast and was fully recovered before filming began.
Coolio: As the "banker" who takes bets during Barbara's bike race. His cameo was supposed to tease his appearance as Jonathan Crane/The Scarecrow in the unproduced sequel Batman Unchained.
Joel Schumacher: [cast] Kimberly Scott and Michael Paul Chan, who play scientists at Gotham Observatory, also appeared in Batman Eternamente (1995) but in different roles. In the previous film, Scott played Bruce Wayne's assistant whereas Chan appeared as a worker at Wayne Enterprises. Schumacher frequently used them in his movies.