The tagline on the early release posters was "The BIG Laughs Start January 6th!" for a January 6, 1992 US theatrical release date however, the US theatrical release was postponed to July 17, 1992.
Much of the the dialogue between Mr. Szalinski and little Adam, such as the bedtime story and feeding time, was improvised by Rick Moranis in response to whatever Daniel Shalikar and Joshua Shalikar, the twins who played Adam, happened to say.
At the beginning of the film, when Wayne first goes into Adam's room, the meowing Kit-Cat Clock (from Honey, I Shrunk the Kids (1989)) can be seen in the upper-left corner of the screen.
When Adam is in the dining room, he knocks one of the light shades from a fixture hanging from the ceiling, but in the next shot, the shade is back in place.
In one scene when Adam is on Fremont St. in downtown Las Vegas the marquee for Circus Circus is behind him. However, all the other signs are for casinos on Fremont St. The Circus Circus sign is not shown again.
Early in the film Dr. Henderson storms out of the lab and walks past a portrait of Clifford Stirling. In the following camera shots, he is directly in front of the portrait then beyond it again.