Continuity mistake: Near the beginning when Lee Van Cleef looks at the the wanted poster on the ticket booth at Tucumcari (just after getting off the train), there are two extra zero's drawn onto the poster (as added by the villain). Van Cleef then takes this poster away with him, and slots it under the door of a hotel room on a later scene - notice that the additional zero's have since disappeared from the same poster.
Revealing mistake: After Manco beats up Cavanaugh and places Cavanaugh's back up against the bar, while Manco faces him, three of Cavanaugh's henchmen appear at the entrance of the bar demanding that Cavanaugh be released. Manco turns around and kills all of them with his pistol, while Cavanaugh falls to the floor crawling toward his gun. Manco is walking toward the entrance of the saloon with his back to Cavanaugh. Manco draws his gun and kills Cavanaugh without looking at him. If you look closely at the tip end of the pistol, you can see that the only thing that Manco would have killed was the saloon floor.
Other mistake: At the beginning of the film, you see Colonel Mortimer traveling on a train while reading a bible. He has a Indian squaw and a gentleman wearing glasses and a derby sitting across from him. A conductor comes by to pick up their tickets. Colonel Mortimer asks the conductor, "is it far to Tucamcari?" The conductor replies, "we pass there in three to four minutes." The gentleman with glasses starts to tell the Colonel that he is on the wrong train. As he tells him this, look out the train window and see a car driving off into the distance.
Revealing mistake: About an hour and a half into the movie Clint Eastwood forces a telegraph guy to send a fake message saying the bank is being robbed, in a nearby town - as a ruse. In the next scene, when the posse rides down a dirt road,you can see tire tracks as they are all coming down a hill and going around a bend.
Add timeroy sandefur
Continuity mistake: The "Man With No Name" rides out of town after collecting his reward for Cavanaugh on a red colored horse. He arrives in El Paso on a brown horse with a different saddle. After he kills the three men he was sent out with to rob a bank he mounts a brown horse but arrives at the telegraph office on a red horse. It is obvious he rode straight to the telegraph office. He leaves the telegraph office and is riding the brown horse again.
Add timeJerry Noble
Continuity mistake: When Manco is dealing the cards, the position of the cards dealt to Cavanaugh change over and over with each card dealt. A coin is visible on one card dealt, then it is gone on another deal. Manco's stack of cards he deals to himself also change from a neat pile to a slightly askew pile.