Deliberate mistake: Near the beginning, Col. Mortimer takes down a wanted poster and goes after the man. The man he kills looks nothing like the man pictured on the poster.
Suggested correction: There is a similar situation in the UK produced western movie "Carry On Cowboy" (released 1965). Johnny Finger/The Rumpo Kid (Sid James) shoots the sheriff of a US town. The sheriff is related to legendary sharpshooter Annie Oakley (Angela Douglas) and she swears revenge. Finding that Johnny Finger is staying in a saloon, Annie Oakley sets up a trap on the staircase. Another person (an uncredited extra) inadvertently walks up the staircase, so she shoots him instead. As he falls down the stairs she calls out "I'm terribly sorry I thought you were somebody else." Perhaps Col Mortimer has made a similar mistake. Being less polite than Annie Oakley he does not have the good manners to apologise.
Suggested correction: Is that a mistake? (Either on the part of the people who made the film, or assuming this was real life, on the part of Colonel Mortimer?) They're a pretty bloodthirsty lot in this film, and nobody seems to really care who gets shot. Maybe he figures he can get a bounty for that person anyway.
Deliberate mistake: When Prince Hapi says that Monique should be his seventh wife, she says "you have seven wives?" and he confirms. Actually if she is supposed to be his seventh wife he only has got six wives by now.
Deliberate mistake: At the beginning of the movie Mr. Coates tells his wife that he will be gone "all of three months, maybe four." The first time we see Bud and Elizabeth Searcy she tells Travis that her dog is pregnant and that Old Yeller is the father. We then see her dog that does not look very pregnant. The next time we see Elizabeth she presents Travis with one of the pups. The problem is that the pup that was supposedly just born is about 4 months old.
Deliberate mistake: When Raza is chasing the "empty" train, as it goes over the trestle just before he stops it, you can see the engineer in the train's engine.
Deliberate mistake: In the final battle where El Guapo's men are fighting the townspeople, look closely to see that they are really just fighting Lucky, Dusty, and Ned. When the towns people appear, their outfits are very different from the real Amigos.
Deliberate mistake: In the scene where the characters are initially signing up for the contest, Gene Hackman's henchmen cock their weapons as they enter, then after Sharon Stone shoots the rope apart the henchmen cock their rifles again. The problem is that with a second cocking the rifles would be ejecting any chambered brass. It seems like a deliberate mistake because they cock their rifles an inordinate number of times throughout the movie; I would guess the director wanted the effect of hearing the weapons being cocked multiple times at the expense of continuity with the rifles.
Deliberate mistake: In the beginning, when the two black workers are using the handcart, they bend their arms as they crouch down to give the illusion that they are slipping into the quicksand. (00:06:30)
Deliberate mistake: When the saloon patrons pour through the swinging doors in pursuit of Packer, the same people are seen repeatedly. A relatively small number of extras are running around to the rear of the set and re-entering through the back so that they will appear to be a larger crowd of people.
Deliberate mistake: While done for comedic effect, the ram's penis as we see it is not what a real one looks like, most noticeably is the missing urethral process.
Deliberate mistake: During the train sequence at the end of the film in 1885, it is blatantly obvious that the train is not going the speed that the DeLorean's speedometer is showing. In some shots, the train looks as though it is going little more than 20mph. (01:38:55)
Deliberate mistake: When Clint Eastwood rides into town the first time,one of the buildings has tarpaper on the outside and doesn't seem to be from the same era.This is the first and last time that building is in any shots.
Deliberate mistake: When Wyatt comes out of the Oriental and joins his brothers in the street to tell them he's acquired a quarter interest in a game, a herd of cattle is passing them in the street but there's no dust kicked up by the cattle, when in reality there would be a lot of dust on a dry desert street in Arizona.
Deliberate mistake: In the beginning of the film, the horse-drawn carriage driven by McGivens is able to crash through a brick pillar and keep moving forward... yet just one minute later in the scene, it's flipped and destroyed by a rope attached to a flimsy wooden spool. There's no consistency to the strength of the carriage.
Deliberate mistake: At about 1:49 in the movie, Glass is awakened by an attacking force of Arikara, and he fires his single-shot, muzzle-loading flintlock pistol at the nearest one coming at him. Then he runs to his nearby horse and flees, turning back to fire the gun a second time immediately. No reloading and no second gun on his person. It never leaves his hand; he's whacking the horse's rump with it to goad it on as soon as he jumps on it. And then he fires that same gun another time in a matter of seconds. (01:40:00)
Deliberate mistake: During Alejandro and Elena's duel, he slashes her skirt and reveals her bare leg. When he slashes off her whole gown, she's somehow wearing leggings. Obviously so Catherine Zeta-Jones would not be naked.