Revealing mistake: Towards the end of the film when the old guy (Ed Begley Sr) is shooting a rifle at Clint Eastwood, the thumb of his left hand is on the top of the barrel, preventing him from seeing the front sight.
Revealing mistake: In the second hanging scene (with the speech of the whisky) Clint Eastwood is looking at the judge's window and he sees him watching. If you look at the window, you will she a big shiny circle over it, probably from the flashlight.
Revealing mistake: Towards the end of the credits, on the highest mountain peak, you will see an air traffic light flash twice.