Batman reveals that Commissioner Gordon is the same age that his father, Thomas Wayne, would have been if he were still alive. This implies that Batman sees Commissioner Gordon as not just a friend, but a father-figure as well.
At 18:00 of the DVD, police radio says attention all cars suspect sited at corner of Adams and O'Neil - fans of the Batman comics will recognize the names as the pivotal creative team of artist, Neal Adams and writer Denny O'Neil, who got the Batman character back to his darker roots in the early 1970s.
While this may have been unintentional, the Jazzman's appearance and low key mannerisms may have been based off of a younger Jack Palance. In the Batman Mythos, Palance played Carl Grissom, a mob boss, in Tim Burton's Batman (1989).
First appearance of Barbara Gordon.
Batman's line to Leslie about having "promises to keep" is a reference to the final lines of Robert Frost's poem "Stopping by Woods on a Snowy Evening" : "But I have promises to keep / And miles to go before I sleep."