One shot of an explosion that was first used in the Superman episode is used at several points in the episode. It's first used when the Mutant Leader's torch is blown up, then as Robin destroys a grenade launcher, when Batman punches the Mutant Leader, as one of the first explosions in the cinema and finally when Batman throws an explosive Batarang to provide the children with an escape route.
At the end of the first story, Batman and Robin shake hands and Batman refers to Robin as "old chum". The handshake was part of the animated title sequence in the 1960s show.
Joker's plot in the second story is to steal the original score of Ruggero Leoncavallo's, "Pagliacci" and 1892 opera that often shows up in Batman media. Penguin and Veronica Vreeland previously attended the opera.
A character named Joel Schumacher's description of Batman (tight rubber suit, with a car that can drive up walls) is taken from aspects of "Batman Forever". (Joel, with his long hair, is himself a reference to the film's director, Joel Schumacher.)