This marks the first appearance of the Ace Chemicals plant since Wrath of the Villains: A Dead Man Feels No Cold (2016).
Valeska's chemicals contaminating the Gotham River is a reference to Detective Comics #475 (February 1978), in which the Joker decides to poison Gotham's water system with his hideous Laughing Toxin, leading to the creation of the infamous Joker Fish.
The episode is the first to reveal the film Mark of Zorro as the film that Bruce and his parents watched on the night of the murder. Prior to this episode, tie-in materials for the series simply referenced it as a musical.
The episode showcases the first onscreen appearance of the Monarch Theatre on the show. Prior to the episode, the theater appeared unnamed in the tie-in novel Gotham: Dawn of Darkness.