When Van Pelt enters the gun store, the music playing on the radio has been modified for the Mexican release due to the fact that, at least in the U.S. release, it originally featured Mexico's national anthem. It is an infringement of Mexican law to play the anthem for commercial or mockery situations, deliberately or not, although in the U.S. Territories it is in the public domain.
Although Carl Bentley is shown to have still been an adult when Allen Parrish was a child, David Alan Grier, who plays Carl, is actually four years younger than Robin Williams, who plays the adult Allen.
The novelization contains an explanation for why Nora had to talk with the principal after Peter and Judy's first day: the realtor's son called Judy out on her lies, and Peter started a fight with him.
The music heard on the radio while Van Pelt is in the gun shop (the Mexican national anthem in the US release) is from a Berliner Gramophone disc record performed by Sousa's Band, recorded 7 April 1898.
The gun shop owner asking Van Pelt if he's a postal worker. Around the time of the movie, there had been a lot of news stories about postal workers going crazy and shooting up their workplaces, from which we get the expression "Going Postal."
When asked in a roundtable interview whether Parrish's father was like Robin Williams' own, the actor admitted a slight comparison. "He was a bit stern and kind of elegant," Williams said. However, the actor likened the disconnected relationship between Alan and his father to the fractured relationship between his dad and grandfather. "The wonderful thing about [my dad] is he would never force me to do anything ... because something had happened early in his life where he didn't want that to happen to me. He had to give up a dream," Williams continued. "His father had been very wealthy and when his father died, they lost all of that and he was forced to work at a strip mine in Pennsylvania ... When I found something I loved, [my dad] saw that ... That's what makes it nice, when you can connect on that level."
The Sir-Save-A-Lot scene was shot in Tsawwassen, BC located at 56th Street & 12th Avenue in what was the Tsawwassen Shoppers Mall. The Sir-Save-A-Lot store was the old Super Valu store (which was a grocery store before it closed). At the time of filming, the store was vacant, and although the exterior was repaired after the movie was shot, the store never re-opened. The mall has since been redeveloped, with Safeway being the anchor tenant. The Sir-Save-A-Lot/Super Valu in the old mall was along the west perimeter of the current mall, what is now a parking lot/entranceway.
During a guest appearance on "Clive Anderson All Talk" (1996)_, a UK chat show, Robin Williams told a story about when he was filming the scene where Alan wrestles a crocodile. He said that in one take he got a little carried away and thumped the crocodile with his elbow, forgetting that there was a man inside the suit. He heard a voice inside the crocodile yell "Hey!" in protest.
The trivia items below may give away important plot points.
Though the movie's plot differs greatly from that of the book on which it is based, the ending of the film is very similar, in which the game is found by two other young children. In the book, the two children who find the game at the end are named Walter and Danny, the main characters from Zathura: A Space Adventure (2005).
In the French version (dubbed in Quebec, at least), Judy's line, "I'm sorry, dear, you have the wrong number," which she speaks in a fake English accent, is still in English but is spoken with a regular North American accent. Additionally, the two French girls who hear the game at the very end speak Spanish instead of French.