Bruce and Terry watch "Batman: the Musical". All the actors on the stage (Batman, Gordon, the Joker, the Penguin, etc) played by the same voice actors as they were in "The Batman/Superman Adventures". The second song of the musical is taken from a 1939 Batman comic book where Batman says to Gordon, "Criminals are a superstitious and cowardly lot..."
Though uncredited, Kevin Conroy also provided the voice of his on-stage double. This marks only one of two instances in the DCAU when Conroy has exhibited his fine singing voice, the other being the Justice League Unlimited episode "This Little Piggy".
The Batman musical featured in Out of the Past is a nod to an actual planned Batman musical which was to feature music and lyrics written by Jim Steinman, of Bat out of Hell fame. The musical was announced in 1998, but canceled in 2005. Some of the songs written by Steinman for the intended Batman musical, "In the Land of the Pig, the Butcher is King" and "Cry to Heaven" were later sung by Meat Loaf, a regular collaborator with Jim Steinman, on the album Bat out of Hell 3.
The women whose pictures Bruce looks at in the Batcave before Talia's are Zatanna, Lois Lane, Selina Kyle, and Barbara Gordon. In "A Touch of Curaré", Barbara implied that she and Bruce had once been involved. The pictures on Bruce's Batcomputer and Talia's line about her knowing he loved her corroborate this.
During the Terry and Bruce team-up, the futuristic Batman: The Animated Series leitmotif previously played in "Disappearing Inque" can be heard.