When Billy shoots Ruffalo, Price drops his drink and starts to fall backward before the shot is heard and the blood spurts from his chest.
Just after the scene where Cain and Billy shoot the branches of the tree, a white VW Beetle can be seen driving behind the trees in the background.
Cain's gun is supposed to have 12 notches, but a closeup shows only 8 notches.
As Anne Francis comes out on her porch when she hears Clint Walker hammering on her gate, a rocking chair is rocking, as though someone had just jumped out of it and run out of the scene.
When Clint Walker peeks over the curtain to watch the cowboy shoot bottles, the cowboy hits two bottles at the same time with one shot. This happens twice, even though the bottles are 4-5 inches apart.
Although the film is set in 1891, Anne Francis's hairstyle, makeup and clothing are current for 1968.
During the prison break, a guard fires a Gatling gun. The sound is that of a high fire rate, modern machine gun. The rate of fire is also several times faster than the rate of muzzle flashes.