The Joker appears as a "wild card" linked to the mobsters' past. 🎮 LEGO DC Super-Villains Guide
"The Gotham Expo" level is a direct homage to the film's finale.
It takes place within the Batman: The Animated Series (BTAS) continuity, specifically set between May 1992 and January 1994 .
In the Expo area, you must drop a ball into all three pockets of the techno panel to progress.