Vincent Schiavelli (Zatara) is one of only five actors from the show who appeared in one of the four Burton/Schumacher live-action Batman movies- in his case Batman Returns (1992) as the Organ Grinder.
Originally Gentleman Ghost was meant to be the antagonist in this episode, but producer Alan Burnett shot the idea down, due to being too supernatural, and as a result was replaced by the somewhat forgettable Montague Kane. This would've made him a Rogues Gallery Transplant (due to him normally facing Hawkman), long before Batman: The Brave and the Bold did so. He eventually appeared in Justice League Unlimited in a small cameo fighting Hawkgirl.
This episode and Night of the Ninja (1992) are the two episodes that show a young Bruce Wayne training.
Alfred asks whether Bruce saw Zatanna 10 or 12 years ago, which Bruce seemingly confirms to be the latter or even longer, giving something of a timeframe for certain events of Bruces life.
This is Zatanna's first appearance.