Continuity mistake: When the bad guy winds up to throw the dynamite into the cantina, McNally puts a round through his brisket, and he falls to the ground clutching his belly. He weakly tosses the dynamite, then stumbles back behind the adobe, now clutching his right shoulder.
Continuity mistake: When Paris has his private meeting with Woodward, he's smoking a cigar and you can see smoke rising all around him. The camera angle changes to a wide shot and all of the cigar smoke is gone.
Continuity mistake: When Jack and Mrs. Pendrake meet in the whorehouse and talk through a screen of glass beads, Jack is standing very close to the screen, that's why it's out of focus when the camera is on her "looking through his eyes". However, in one shot it's not, and that looks quite strange because Jack hasn't moved away from the screen. (01:46:35)
Continuity mistake: The third time we see the stagecoach on its way to Denver, it's passing the exact same tree and hill that it passed at the start of its journey. It's also traveling on a paved road, which in 1860s frontier Colorado is extremely unlikely. (00:11:15)
Continuity mistake: When the Bannister gang begins shooting at the house, the ladies abandon their breakfast to run and hide upstairs. There's a pitcher half full of milk on the table. But a few shots later, when one of the Bannisters bursts into the kitchen, the milk pitcher is empty, and the dishes are in different positions on the table. (01:23:55)