Revealing mistake: At the cave near the end, there are several scenes with the secretary of the interior. These scenes with the main actors appear to be filmed in front of the background as they cast shadows on the other film and the lighting is different. This was most likely done because of budget limitations.
Revealing mistake: After Joe (Clint Eastwood) shoots dead the five men in the "small house" there is a close-up shot of one of the dead men lying across the table and his eyes are still open. Joe then pushes him off the table and as his body falls the dead man closes his eyes. (01:02:38)