Acting for Two: Kevin Kline as both Gordon and President Grant, including instances of talking to himself. Then there's the scenes where Gordon impersonates Grant and this gets really weird.
Box Office Bomb: In the U.S. Budget, $170 million. Box office, $113,804,681 (domestic), $222,104,681 (worldwide). Will Smith famously joked about this, saying "That's how big I am. I bomb over a hundred million."
Completely Different Title: The movie was called As Loucas Aventuras de James West (The Crazy Adventures of James West) in Brazil and Las Aventuras De Jim West (The Adventures of Jim West) in Latin America.
Barry Sonnenfeld had a lot of problems with Jon Peters' Executive Meddling, but he particularly had a problem with the scene where Will Smith dresses up as a harem dancer to distract Loveless. He said if he had more clout at the time, he'd have walked from the film at that point.
I never wanted to see Will in drag. I thought it was prurient, unnecessary, silly and in there only because Peters loved it and refused to let us take it out. We really lose the audience from there till the end of the movie because of the stupidity of that weird harem dance. I cringe every time I think about it. Until the dance, it's a good scene. Loveless is scary, and the audience believes that he's going to take over America. But then it's like, "Oh wait a minute, I'm gonna forget all that because there's a harem girl who I didn't invite — I’ve no idea how she got here — but boy she's sexy, and who wants to take over America when there's a girl in a green harem outfit next to me?" It. Made. No. Sense.
Despite enjoying his work on the film, Ted Levine admitted that the film's storyline was all over the place due to the constant changes of the script and attributed this along with Will Smith's casting to the film's failure.
S.S. Wilson and Brent Maddock admitted that it wasn't the film they were hoping for due to the constant scriptwriting changes without their knowledge.
Will Smith himself has since acknowledged how awful the movie was, especially considering he turned down the role of Neo in The Matrix to make this instead (though he's admitted that the latter, at least, wasn't a mistake, as he doesn't believe he could have made Matrix justice). He's been a little nicer to this film, however, in the wake of bigger disappointments like After Earth (which came out the same year as The Lone Ranger, which killed the superfluous Western a second time), and it helps that his son Jaden didn't mind the film either. (Even on Smith's 1999 album Willennium, when his father asked him which song to put on the CD next. Jaden Smith, a toddler at the time, requested the film's theme song).
Barry Sonnenfeld, Kevin Kline, Salma Hayek, and in fact half the staff at Warner Bros. feel the same way. Hayek in particular thought she was being underused, while Kline considered himself too good of an actor for the finished product.
Kenneth Branagh self-deprecatingly joked that his accent in this movie might be the worst American accent performed by a British actor.
Was this for Barry Sonnenfeld as a film director, as he hasn't had more success in said capacity besides the Men in Black series. Today, he's only mostly active in TV.
It was a bigger killer for Jon Peters. He was one of the most well known and actively working producers of the 70's-90's but the failure of the film and reports that he had meddled too much in its making practically killed any goodwill he had in Hollywood; after this movie's failure, he's only produced 4 movies in the span of 20 years- Ali, Superman Returns (which also helped kill his career off), Man of Steel, and A Star Is Born (2018).
Deleted Scene: During their night in the desert, Gordon would reveal he was never a Secret Service agent but rather an actor. He had been driven to aid as he had once been part of the acting troupe with John Wilkes Booth and felt guilty he didn't see the signs of Booth planning to kill Abraham Lincoln.
Directed by Cast Member: In the Italian dub, the late Cesare Barbetti was the ADR director, as well as the voice of Artemus Gordon and President Grant.
Disowned Adaptation: Robert Conrad, who played Jim West on the original TV series, was very vocal in his dislike of the movie, even going as far as personally accepting the Razzies it "won". His dislike started when they asked him to do a Remake Cameo as President Grant; upon reading the script, he described it as an insult to his late coworkers on the series, Ross Martin (Artemus Gordon) and Michael Dunn (Dr. Miguelito Loveless). You'd be very hard-pressed to find a fan of the show who disagrees.
Genre-Killer: This helped put big budget Cattle Punk films in a box for the 2000's, and similarly costly and ill-received attempts to try this genre again with Cowboys & Aliens and The Lone Ranger have sent it back to that box.
The Other Marty: Belle was originally cast with and filmed with British actress Phina Oruche. Reportedly, however, the chemistry needed for the bathtub love scene wasn't there. The scene was re-cast and re-shot with Garcelle Beauvais. Oddly enough, Oruche was not told, and found out she was no longer in the movie at the premiere in Los Angeles.
Saved from Development Hell: The film was pitched as far back as 1992 as a straight-laced film adaptation of the series, to be directed by Richard Donner (who had directed several episodes of the series) and with Mel Gibson slated to play Jim West and a script by Shane Black. The duo ended up making Maverick instead. Tom Cruise was then attached to the project before he decided to revamp Mission: Impossible in its place; only then was the project overhauled into the comedic Will Smith vehicle you see today.
Stillborn Franchise: Any ideas of sequels or even continuing the franchise were left stranded with this movie becoming panned.
Troubled Production: The film's budget spiralled to $170 million and wound up as one of the most notorious bombs of The '90s as a result. This article by Ralph Jones for Mel magazine goes into more detail.
It started when Barry Sonnenfeld, who had been a fan of The Wild Wild West as a kid, was told during production on Men in Black that a Shane Black-penned adaptation of the series had fallen into Development Hell. Will Smith, who Sonnenfeld had directed in Men in Black, quickly signed on to play the hero Jim West, while Sonnenfeld personally vouched for Kevin Kline to play Smith's Straight Man co-star after George Clooney turned the part down. Sonnenfeld had been hoping to repeat the chemistry between the wisecracking Smith and the stone-faced Tommy Lee Jones in Men in Black, but Kline proved to be more interested in matching Smith beat-for-beat with the laughs, partly because he felt threatened by Smith's star power. Perhaps not coincidentally, a common complaint was that their chemistry didn't match up to that between Smith and Jones.
Producer Jon Peters, notorious in Hollywood for his Hair-Trigger Temper, was responsible for many of the film's infamous anachronisms. A scene of West riding a horse, for instance, was replaced with him riding a motorcycle because Peters thought that horses were boring, even though the writers pointed out that the film was a Western set in 1868. However, the infamous giant steampunkSpider Tank from the climax, contrary to popular belief and Peters' reputation for putting spiders in his movies, wasn't Peters' idea; that was in the original script by Brent Maddock and S. S. Wilson, and he actually tried to reject it initially in favor of a giant flying machine, with Sonnenfeld sticking up for it in meetings. Incidentally, the meetings concerning the spider were the last time that Maddock and Wilson heard from Peters.
Reshoots were done to add more jokes and make the film Hotter and Sexier after test audiences complained that it was too chaste. An actress was recast because she had it in her contract that her scenes wouldn't get too raunchy, and Sonnenfeld himself was also horrified by a lot of the humor. Peters was responsible for the scene where Jim West dresses up in drag to seduce Dr. Loveless, largely because Peters thought it was funny, even though Sonnenfeld sharply disagreed and felt that it dragged the film to a halt; he said that, if a producer tried to meddle with one of his films like that today, he'd have simply walked off the set. This also bumped up the budget by an estimated $20-40 million.
During the shooting of a sequence involving stunts and pyrotechnics at the western town set at the Cook Movie Ranch (now Cerro Pelon Ranch), a planned building fire grew out of control and quickly overwhelmed the local fire crews that were standing by. Much of the town was destroyed before the fire was contained.
The film premiered over the Fourth of July weekend in 1999. Reviews were scathing, the box office wasn't much better, and a number of people involved with the original show condemned it, with Robert Conrad, the original Jim West, even personally collecting the three Razzies the film "won" in order to express his displeasure. Virtually everybody involved (save for Bai Ling) treats the film as an Old Shame, though Maddock also regards it as a learning experience.
The part of Rita Escobar was originally offered to Jennifer Lopez, but she turned it down. It was then offered to Penélope Cruz, who also turned it down due to scheduling conflicts with her film Volaverunt. Asia Argento was also considered.
Hans Zimmer was courted to score for the film by Sonnenfeld, he was talked out of it in the belief that someone with more Western experience would be better suited. So Zimmer didn't wind up doing a disastrously received Wes...oh wait.
Non-Trope Trivia
The MAD Magazine satire was called Mild Mild Mess.
This movie earned the Worst Picture of 1999 Golden Raspberry Award, and is the first of two straight Warner Bros. movies to "win" the award; Battlefield Earth the next year is the second.
by Ralph Jones for Mel magazine goes into more detail.