Denzel Washington worked out for three hours a day, six days a week for four months so as not to look out of shape for his shirtless scenes.
John Lithgow almost never blinks during this film. He wore a contact lens to give the impression that his character had a glass eye.
According to many reports, from members of the audience during the first test screening, it was originally much more violent, and it's also been reported, that the final version is heavily cut. Also, according to a foreign interview director Russell Mulcahy gave, a scene where Styles is physically abused by Blake until he pukes, and Blake gets a sponge to clean him up, was one of the scenes that was cut, after the test audience reacted negatively to watching a white man torture a black man. Some trailers show shots of scenes, which are not in the movie.
The film is supposed to take place in the same universe as the Die Hard (1988) franchise, however, some of the supporting characters went on to have different roles in later films, most notably John Amos.