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.
Cinematographer Adam Greenberg was personally chosen for the job by Arnold Schwarzenegger, who had worked with him on both Terminators. Schwarzenegger assured the production that if they wanted an experienced, professional cameraman who could capture the action on the film's hectic schedule, that Greenberg was the man for the job.
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.
Arnold Schwarzenegger really did free-fall for about 65 feet. He was harnessed into a piece of stunt technology called a descender rig. Directly afterwards, director Chuck Russell told Schwarzenegger that there had been something wrong with the camera, and the scene had to be repeated; however, this was immediately revealed to be a prank, as to not upset Schwarzenegger any further.
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.
The original name of the Cyrez corporations was "Cyrex". However, Cyrix, a microprocessor corporation and rival of Intel, protested. The name was then changed digitally in any scenes where the name appeared in a fairly costly process for the time, and dialogue redubbed. Some instances of the "Cyrex" logo are still visible in the finished film.
The film's rail guns are actually based on real military technology, a fact outlined at some length in Roger Ebert's thumbs up review of the film. As Ebert noted, however, the rail gun technology that actually exists was both in a very early development phase and designed to put such weapons on U.S. Navy ships instead of making for anything that an individual could carry and safely discharge.
This is Arnold Schwarzenegger's third film which he plays a bodyguard. In Kindergarten Cop (1990) Schwarzenegger plays a tough Los Angeles cop whom goes undercover as a school teacher, so he can protect a woman and her son from a drug dealer and in Terminator 2: Judgment Day (1991), Schwarzenegger starred as a cyborg warrior from a post-apocalyptic future whom travels back through time to protect a 10 year old boy whom in that post-apocalyptic future is a rebel leader.
The film's tagline is "He will erase your past to protect your future". Arnold Schwarzenegger played two robots from a post-apocalyptic future, one as an assassin sent to back to kill a woman, which will change the future and the other sent back to protect the woman's son and prevent the post-apocalyptic future from happening in The Terminator (1984) and Terminator 2: Judgment Day (1991).
Nick Chinlund portrays WitSec Agt. Calderone, and while on the agency's jet refers to transporting dangerous felons as being "a chauffeur for degenerates". Chinlund later portrays one such degenerate, Billy Bedlam, in Con Air (1997).
The same year as the film's release, Vanessa Williams made a guest role in Star Trek: Deep Space Nine: Let He Who Is Without Sin... (1996) as Arandis and James Cromwell co-starred as Dr. Zephram Cochrane in Star Trek: First Contact (1996).
Danny Nucci later starred in Titanic (1997) which was written and directed by James Cameron whom was the writer and director of Arnold Schwarzenegger's earlier films The Terminator (1984), Terminator 2: Judgment Day (1991) and True Lies (1994).
The trivia items below may give away important plot points.
In the opening credits sequence which Kruger is seen gearing up to rescue Johnny Casteleone in the opening scene, Kruger is seen burning a photo of Lee Cullen. However, Kruger is not assigned to protect Cullen and doesn't know about her until after he rescues Johnny C and Kruger doesn't meet Cullent until after Donohue commits suicide and he burns her photos, her IDs, her credit credits after the first as assassination attempt on her life. How is Kruger in possession of a photo of Cullen, if Cullen has not yet been put in the Witness Security Protection Program?