In the movie theater where the Nick Lang movie is playing and where the Party Crasher gets in the shoot out with Michael J. Fox, there is a poster in the background for Bird on a Wire (1990), also directed by John Badham.
Director of photography Robert Primes was fired halfway through filming by director John Badham and replaced by Donald McAlpine. Badham thought Primes was working too slowly; he had similar complaints during the filming of Bird on a Wire (1990), their previous (and first) movie together.
During the club scene where The Party Crasher makes his first on screen kill, the song "Momma Said Knock You Out" is playing in the background. This was LL Cool J's hit single at the time, and he also features as one of James Woods' NYPD partners in the film.
The film was originally slated to shoot for 16 weeks, but was reduced to 13 because producer/second unit director Rob Cohen was shooting at the same time as John Badham in different locations to save more time and money.
The trivia items below may give away important plot points.
The climatic sequence on top of the Smoking Gunn II billboard in Times Square took ten days to shoot with New York traffic put to a stand still and crowds of onlookers from all over the city including tourists, gathered at night to watch the filming. All local TV news stations, along with those from Europe and South America covered the nightly shooting. The billboard itself was compared to that of the Camel cigarettes sign of the 1950s with smoke puffing from it as a main attraction on Broadway.
According to the baseball cap that Captain Brix puts on (just before the end credits roll), the movie that Nick Lang has been working so hard to nail the audition for is called "The Good, The Badge, and The Ugly".
The billboard used for the climatic sequence in Times Square was originally a flat 2D billboard, but was later changed to the final version seen on screen because it could not be recreated on a sound stage.