Paramount Pictures originally owned the rights to the film, and they wanted a big name star to appear opposite Robert De Niro, in order to improve the film's chances at the box-office. It was suggested that the character of John "Duke" Mardukas be changed to a woman, and be played by Cher, who had had recent box-office success with The Witches of Eastwick (1987), Suspect (1987), and Moonstruck (1987). It was felt that casting Cher opposite De Niro would lend some "sexual overtones" to the relationship between the two characters. Director Martin Brest however, rejected the gender switch idea, so Paramount Pictures suggested giving the role to Robin Williams, who had recently had a big hit with Good Morning, Vietnam (1987). Williams read and liked the script, and agreed to audition. In the meantime, however, Brest had auditioned the less famous Charles Grodin, and had liked Grodin's interaction with De Niro. As such, Brest cast Grodin without auditioning Williams, and Paramount Pictures decided to drop out of the project, selling the rights to Universal, who went ahead with the De Niro and Grodin casting.
The boxcar scene where Jack Walsh (Robert De Niro) and John Mardukas (Charles Grodin) discuss whether or not they could ever be friends, was almost entirely improvised on-set. As regards Grodin's famous, "You ever had sex with an animal, Jack?" line, he was told by Director Martin Brest to come up with something that was guaranteed to make even Robert De Niro laugh.
After doing The Untouchables (1987), Robert De Niro was looking for some lighter material to do next. Initially, he wanted to play the lead in Penny Marshall's Big (1988), but the studio wasn't interested in having De Niro play the role. He was then offered this movie, which he liked, and agreed to make.
The scene where John Mardukas (Charles Grodin) falls off a cliff was shot in the Salt River Canyon in eastern Arizona. However, the conclusion of the scene, the shots of Mardukas and Jack Walsh (Robert De Niro) crashing through the river rapids, was shot in New Zealand, because the water was too cold in Arizona.
Alonzo Mosely's sunglasses are gold-plated versions of the iconic 1978 Porsche Design "exclusive su glasses" model. The Porsche design logotype can be seen in the close-ups of Mosely in the "Agent Foster Grant" scene at the bus station.
Danny Elfman wrote lyrics for the end credits theme "Try to believe". He sang the lead and recorded it with his band Oingo Boingo under the guise of "Mosley and the B-men". This version only appears on the soundtrack album. It was mixed by Brian Foraker.
The theatrical trailer for the film shows several scenes which were not included in the final cut. For example, shortly after Jack (Robert De Niro) has captured Jonathan (Charles Grodin) for the first time, there is a scene where they are driving down a city street at night, and Mardukas tries to escape from the car, causing Jack to point his gun at Mardukas and tell him to make himself comfortable, to which Mardukas responds "I'm very comfortable". Another scene involves Jack, Jonathan, and Marvin (John Ashton) in the car trying to escape from the helicopter, and Jack turns around and yells "They're gaining on us", to which Mardukas responds "Of course, they're gaining on us, they're in a helicopter." A third scene occurs when Jack and Mardukas get the lift from the Native Americans, and as they are travelling along the road, a Native American asks them if they travel a lot, to which Jack and Mardukas look knowingly at one another.
The Blue Angel Motel in Las Vegas was demolished in 2012 to make way for ninety-one thousand square feet of retail stores, restaurants, and entertainment venues. The motel had seen better days, but its iconic statue of a blonde woman wearing a blue dress was preserved. Adored by locals and visitors alike, the statue was designed by Betty Willis, who also designed the Stardust Casino sign, and the world-famous "Welcome to Fabulous Las Vegas" sign.
In one of the scenes filmed in Las Vegas, you can see the sign for the Stardust Hotel and Casino. Frank "Lefty" Rosenthal once operated that casino, and was the basis for Robert De Niro's character, Sam "Ace" Rothstein, in Casino (1995).
When Jimmy Serano (Dennis Farina) is meeting with his attorney, he threatens to bury the telephone on the desk in the attorneys skull. In Get Shorty (1995), Dennis Farina's character (Ray "Bones" Barboni) hits Gene Hackman's character (Harry Zimm) in the head with a telephone.
Mel Gibson, Kurt Russell, Michael Keaton, Richard Gere, burt reynolds, Clint Eastwood, Charles Bronson, Gene Hackman, Tommy Lee Jones, John Travolta, Arnold Schwarzenegger and Sylvester Stallone were considered to play Jack Walsh.
Audio book narrator Hubert Williams was an extra, playing a Blackjack dealer while the movie was shooting at the Aladdin Hotel in Las Vegas. Two of the Aladdin security guards, noticing the Aladdin uniform he was wearing, tried to make him leave the area. A member of the crew had to explain that Hubert was involved in the movie. It was the first of many times that Hubert appeared as an extra in movies.
In the latter part of the film, there is a shot of Jimmy Serrano and his associates walking from a taxi into a casino in Las Vegas. The Dunes Hotel's sign is clearly visible against the sky in the background, and its hotel tower can be seen at the left edge of the screen. This indicates that the camera was pointed toward Las Vegas Boulevard from the Dunes property. The Dunes closed in 1993, and The Bellagio was built on its former grounds.
There are two references to types of Hispanic meat in the film. The villain is called "Jimmy Serrano", and "Serrano" is a type of dry-cured Spanish ham. In the restaurant, Jack and John are offered Chorizo and eggs, the waitress helpfully explains that Chorizo is a Mexican sausage.
According Joe Pantoliano (Eddie Moscone) in his interview on Gilbert Gottfried's podcast, Director Martin Brest gave him the opportunity to play one of the two goons that was always chasing De Niro's and Grodin's characters. But he wanted to play Grodin's part (which was flat out rejected) or the role he ultimately got after auditioning for it.
The trivia item below may give away important plot points.
The train scene in Flagstaff, Arizona, actually prevented a kidnapping, at the end of the "searching the train" scene, filmed in downtown Flagstaff. Rick Long and I (Waysie Atkins) were extras, dressed as policemen, and driving "police vehicles". Word arrives that the suspects have been spotted near Sedona. At this point, a dozen or so "police cars", driven by extras, leave the train station toward Sedona, via downtown Flagstaff. Two men were in the process of kidnapping a young women from a coffee shop in downtown Flagstaff right as the dozen or so "police cars" drove past the coffee shop. The attempted kidnappers were spooked into thinking they were being chased by real policemen, and threw the girl down, and fled the scene of the attempted kidnapping.