Continuity mistake: When Paris is offering all the other prisoners half of his hidden money for a way to escape, he lays down in his bed with his cigar in his mouth and his arms at his side. The camera angle changes to a wide shot of the holding cell and the cigar is now in his right hand near the edge of the bed.
Continuity mistake: When Paris is making friends with the guy who shot a cop in the prison yard there is no shadow on Paris' face as he is talking. As a matter of fact, the shot looks like he has a huge bright light focused on him. When the guy who shot the cop is talking it is a different time of day. You can see shadows on his face and the background light is lower.
Continuity mistake: When they dump The Missouri Kid in the bath water, they turn him upside down and dump him into the barrel. You can see that it is not Burgess Meredith and a much younger man. He even grabs the edge of the barrel so he can help guide himself in. You then see one of those flim "flicks", where the camera angle has changed just a bit, before The Missouri kid rises from under the water.
Visible crew/equipment: When Woodward has Paris draped over his horse, he's leading the horse back to the prison and you can see the square piece of black equipment they added to the foot rest of the saddle, that the stuntman is holding on to so he doesn't fall off the horse. When Woodward arrives at the prison, it's gone.
Continuity mistake: When Cyrus goes to hang himself, the first camera angle is from Paris' perspective and you can see that Paris is playing the card toss game into a small basket. The camera angle changes to a wide shot and the basket in not there anymore. Happens about three times during angle changes.
Continuity mistake: Paris dies next to the horse he got from the widow. When Woodward brings him back to prison Paris is draped over a mule, not his horse.
Other mistake: When Paris gets to prison he has a wad of money on him. Before he got that far the court would have taken the money away and given it back to the guy he stole it from.