Another sequel titled "Grumpiest Old Men" was planned. It was to be filmed in Rome and feature Marcello Mastroianni as Maria's former husband who contests her marriage to Max on the grounds that their divorce was never finalized. But the film was canceled due to the box-office failures of Out to Sea (1997) The Odd Couple II (1998).
In the first movie Grandpa Gustafson says he's 94 years old. In
the second movie he says he just turned 95. So less than a year has passed but somehow Melanie's daughter Allie aged 3 or 4 years.
During the "Chicken Dance" scene, when the couple are fighting, the dancing doesn't match the music. The Chicken Dance has a specific set of actions for various points in the song - this was blatantly off.