Inside the shack during the stand-off, the amount of lighting used changes dramatically between shots.
In the opening sequence just after the wheel repair, the rear suitcase was tilted upward at the right side. In the next cut the suitcase is tilted upwards to the left.
Near the start of the picture, when Dr. Garth is eating with the cowboys, she picks up her cup of coffee twice between shots.
In the shack during the standoff, David is shown to operate the lever action on his rifle, which chambers a round and cocks the hammer. In a following shot he manually cocks the hammer again.
At least twice in the film's dialogue, the late-19th century father of antiseptic surgery, Joseph Lister (1827-1912),1st Baron Lister is, for some obscure reason, incorrectly referred to as "Jacob Lister".
In the opening scenes when the wagon reaches the outskirts of town, many large, modern buildings are visible behind the town. None of that is visible once they're in town.
In some shots at the settlement with the hospital and O'Brien's hacienda, power lines and poles are visible.