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.
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.