Continuity mistake: In the barn, when Artemus jokes about "smoked ham," he and West are standing within inches of each other. Then the shot cuts to a wider angle, at which point they're several feet apart.
Continuity mistake: It's just past nightfall when the townspeople enter the courthouse. They aren't there more than half an hour, yet it's daylight when they emerge. Then a shot from inside shows that it's night again.