In the scene with Barbara Gordon's roommate in college, the background music is "Am I Blue", which has another connection to Batman. It also is featured in the animated Justice League: This Little Piggy (2004), in which Batman sings this song on stage in order to save a friend. Batman & Mr. Freeze: SubZero (1998) and Justice League are part of the same larger universe and continuity.
Was originally set for a release in the summer of 1997, but held back because of the negative reception following the release of Batman & Robin, which also featured Mr. Freeze as an antagonist. Nevertheless, upon release, the film received strongly positive reviews, compared to Batman & Robin.
The numerous addresses shown within the film place Gotham City withing the state of New York, and all phone-number area codes and ZIP codes correspond to New York City. New York City was one of the original inspirations for Gotham City.