In the cave, Kemp (James Stewart) gives Vandergroat (Robert Ryan) the pistol; in five subsequent scenes, the pistol alternates from being inside his vest, to outside his vest, to inside, to outside, and finally to outside but leaning way over about to fall out of his pants. In the scene changes, Vandergroat supposedly didn't move except to lower his hands during the first sequence, but when the camera changed from Kemp to Vandergroat and back several times, each time the pistol position alternated from inside the vest to outside.
Right after Jesse offers to rub Ben's shoulder, he places his hand on Ben's left shoulder. In the next shot, Jesse is still holding his rifle with both hands.
In the opening sequence when Jesse Tate turns to face Howard Kemp, in one shot (from behind him) his hands are low (behind him). In the next shot from behind Kemp, Jesse's hands are raised.
The amount of dirt on Ben's hands changes when Kemp drags him through the cave.
When Howard and Jesse meet Lieutenant Roy Anderson for the first time, Howard asks for his discharge papers, which states he has a dishonorable discharge. Officers do not receive dishonorable discharges; an officer found guilty in a court martial receives a dismissal. Otherwise, they may retire or resign their commissions.
When Roy surprises Ben on top of the cliff they struggle and roll around, at one point they roll over softball-sized rounded rocks. Rocks like these are formed by glaciers when they are smoothed and rounded as the glacier pushes them along. They are deposited when the glacier melts away. This would be in river beds at the bottom of valleys, not on the top or side of a mountain.
In the final scene by the river, the noise of the river would make it near impossible to hear voices at a distance. Vandergroat's calls to Kemp to lure him to help Lina would not have been heard.
During the Indian fight, most (if not all) of the Indians' horses survive, but as the party leaves, Ben is still riding Jesse's burro. They would have rounded-up all the available horses, not just for Ben, but to have horses to alternate on their ride.
After the fight with the Indians, when Anderson breaks cover and moves towards the others, one of the dead Indians can be seen to move.
The movie is set in March of 1868, as denoted by the wanted poster and Lt. Roy Anderson's discharge papers. However, the revolver used throughout the movie is the Colt Model 1873 Single Action Army. Also the rifle should be the Winchester Model 1866 "Yellow Boy", so named because of its yellow-colored receiver; it is obviously a later model Winchester lacking the coloration.
The wanted poster indicates the film takes place in 1868. However, Howard Kemp wears a California Conservation Corp jacket, which wasn't available until 1935.
As Roy Anderson climbs a rope up the cliff side, the cable holding him safely in place is visible alongside the rope.
(at around 14 mins) When Roy Anderson is attempting climb a boulder with a rope, an equipment shadow can be seen on the portion of the boulder closest to the camera.
After all the travelling, the party ends up at the same place where Vandergroat and Lina were hiding originally, although it is meant to be a different location.