When Nicky is talking with the Asian people on the street, you can see in the background Tom's Restaurant which "plays" Monk's Diner in Seinfeld (1989).
Marilyn Manson, known for his devilish imagery, was originally going to have a role in the movie but he later had to bow out due to conflicting schedules.
This is the 4th Adam Sandler film to have a love interest with initials "VV" with Patricia Arquette as Valerie Veran. First was Billy Madison (1995) (Veronica Vaughn); second was Happy Gilmore (1996) (Virginia Venet); third was The Waterboy (1998) (Vicky Valencourt).
After Nicky has fought Adrian for the final time, two girls in back of Nicky have no jackets on in one shot, and then are wearing jackets in the next. In the third frame, they again do not have jackets on.
At the very beginning when Nicky is "air jamming" to Van Halen's "Runnin' With The Devil" (which is playing on the right turntable), the turntables have no covers up until just before Jimmy The Demon walks in, then they are covered after that.