Trivia: Batman: Under the Red Hood
- Casting Gag:
- Digital Piracy Is Evil: The movie was leaked online a full two-weeks before its intended DVD release, available for download on at least two separate file-sharing websites on July 13, 2010. Didn't stop it from being one of the best selling of the DC series films, though.
- Fake American: Canadian-born Bruce Greenwood as Batman.
- Playing Against Type: John DiMaggio as The Joker.
- What Could Have Been: The film was originally going to be R-rated, but Warner Animation convinced the staff to tone it down to PG-13. The preview of the movie included with Justice League: Crisis on Two Earths contains clips of the R-rated version of Joker killing Jason, which are noticeably bloodier and more violent than the final product.