The company name "Cyrez" was originally "Cyrex", but the real-life company Cyrix complained. The movie had been shot, but all dialogue was dubbed and company logos were digitally altered during postproduction.
Director Chuck Russell and producer Arnold Kopelson had a rocky relationship during the entire production. The only reason the film was able to go forward and ultimately be completed (albeit way over schedule and budget) was that Arnold Schwarzenegger got along with each man separately and was able to negotiate schedules and logistics at a point where the two men refused to speak to each other.
The shot outside of the gay bar in DC showing the US Capitol Building was actually taken outside of the Phoenix Park Hotel on North Capitol St. in DC. The front of the hotel was covered in purple and the "AC/DC" fictitious bar name prominently displayed.
Although only Tony Puryear and Walon Green are credited with the film's screenplay - and the two of them along with Michael S. Chernuchin for the film's story - the film went through so many revisions from so many different writers that the final shooting script reportedly "looked like a rainbow". Frank Darabont and William Wisher Jr. reportedly did multiple rewrites during the production as well.
John Kruger using two EM rail guns as weapons in the Baltimore Docks battle mirrors a Terminator using two Endo Rifles in the opening future battle sequence in Arnold Schwarzenegger's earlier film "Terminator 2: Judgement Day", which Schwarzenegger starred as The Terminator.
Arnold Schwarzenegger and James Caan have both starred in films about violent futuristic game shows in totalitarian societies. Cann in "Rollerball" as Jonathan E. and Arnold Schwarzenegger in "The Running Man" as Ben Richards.