When Johnny sends his mother to the neighbor's house before the mobsters show up, she says "I'll be at May Parker's." May Parker was the name of Peter Parker's aunt in the Spider-Man comics and lived in Queens, where the movie takes place.
The song that the band at the club plays is "Symptom of the Universe" by Black Sabbath. Ozzy Osbourne, who plays their manager, was the original lead singer for Sabbath.
Writing and filming sessions for this movie commenced around 1993, but its release was delayed because the film's original distributor, Buena Vista, did not know what to do with it. Finally, Buena Vista and Touchstone Pictures bought the rights to the film in 1994, and it was officially released in 1995.