- Missing Trailer Scene: In a unique application of this trope, the commercials for this movie consisted entirely of scene from Mr. Freeze's previous appearances on Batman: The Animated Series.
- The Other Darrin: Melissa Gilbert was replaced by Mary Kay Bergman as the voice of Barbara Gordon. Tara Strong would replace her when Batman: The Animated Series became The New Batman Adventures.
- Out of Order: The film was released in the middle of The New Batman Adventures, but takes place before or during the Time Skip and uses the original art style. It was originally meant to be released before The New Batman Adventures in mid-1997 as a tie-in to Batman & Robin (which also features Mr. Freeze), but that film's overwhelmingly negative reception caused the studio to delay SubZero's release by almost a year.
- The Shelf of Movie Languishment: The film was meant to be released in 1997 to be a psuedo-tie in with Batman & Robin, but due to scathing reviews of the live-action film, it was delayed after completion to March 17, 1998.
- Shrug of God: Is this film set before or after Batman finds out Barbara is Batgirl? It was constructed so as not to contradict either possible answer. It's clearly set before Robin did, given the flashback in "Old Wounds" shows Dick quitting the same night he learned it.
Trivia / Batman & Mr. Freeze: Sub-Zero