- Deleted Role: Several characters that never appeared in the second movie are seen in the closing credits.
- Edited for Syndication: On The Hub, there were a few things they edited in both films. Some of the language was a bit toned done in both. Another thing they edited was Junior flipping the bird, Nippy crapping, and of course the Crazy Dance scene.
- Executive Veto: During the "It's My Party" montage, Lucy is sawed in half by the clown. Junior replaces the fake saw with the real saw, which ends up cutting off Lucy's dress, revealing her underwear. The scene was cut as too risqué.
- Follow the Leader: Implied. The Nostalgia Critic states in his review of the first film that Junior would become the template for every "disobedient 90s son" that would follow afterwards like Bart Simpson due to the film being released in 1990.
- Harpo Does Something Funny: John Ritter and Gilbert Gottfried were given full reign to ad-lib whenever they wanted.
- The Other Darrin:
- Junior and Ben were re-cast in the final film.
- Except for Gilbert Gottfried, none of the film cast returned for the animated series. The French dub of the cartoon instead replaced everyone except Junior's child actor.
- Real-Life Relative: John Ritter's real-life wife Amy Yasbeck played Ben Healy's wife in the first movie and his love interest in the second movie.
- Role Reprise:
- Gilbert Gottfried is the only one from the film series to be in the animated series, voicing Mr. Peabody once again.
- The Latin American Spanish dub brings back the entire dub voice cast from the films.
- Same Language Dub: June Foray voices the puppets in the second movie who were operated by the three kids who Trixie later ties up during the Salute to Democracy Puppet Show.
- What Could Have Been:
- Scott Alexander and Larry Karaszewski originally envisioned the first film as both a black comedy and an adult satire of the then-popular trend in films where cute children teach cynical adults how to love.
- Macaulay Culkin auditioned for the role of Junior.
- Dan Aykroyd, Chevy Chase, Richard Dreyfuss, Steve Martin, Rick Moranis, Kurt Russell and John Travolta were all considered for Little Ben Healy. Chase turned it down due to National Lampoon's Christmas Vacation, Martin was occupied with My Blue Heaven, Moranis and Aykroyd were doing Ghostbusters II, Travolta was in Look Who's Talking Too, and Dreyfuss and Russell wanted too much money and Russell was on Tango & Cash.
- Kirstie Alley, Kim Basinger, Carrie Fisher, Mary Steenburgen and Catherine O'Hara were reportedly offered to play Flo. Alley turned it down due to her shooting Look Who's Talking Too, Basinger was busy doing Batman (1989), Fisher was filming Sibling Rivalry, O'Hara was called to do Home Alone and Steenburgen had commitments with Back to the Future Part III.
- Christopher Lloyd was supposed to play the Bow Tie Killer but he turned down the role because of his commitments with Back to the Future Part III.
- According to the screenwriters, 2 was originally much cruder, so much so that the initial cut received an R rating from the MPAA.
- The studio wanted John Landis to direct this film, but Landis declined as he wasn't interested in directing a kids/family film. Joe Dante was also approached. But despite showing interest, he turned it down due to conflicts with Gremlins 2: The New Batch. Richard Donner was also considered to direct, but he declined as he was busy in post-production on Lethal Weapon 2.
- The screenwriters tried pitching the film to several studios including 20th Century Fox, Columbia Pictures and Warner Bros. Fox executive Barry Diller hated the script while Columbia and Warner showed no confidence in the film. They eventually convinced Universal Pictures to greenlight.
- Write What You Know: The screenwriters got the idea for the film from a newspaper article about a couple who sued an adoption agency for giving them a boy with a violent history without informing them beforehand.
- You Look Familiar: Ben's neurotic wife Flo in 1 and his sweet-natured love interest Annie in 2 are played by the same actress. Oddly, no one points out the resemblance. Amy Yasbeck, the actress in question, was Ritters then-wife.
Trivia / Problem Child