Continuity mistake: When we see Maverick for the first time in the hanging scene he is sitting on a horse with a rope around his neck, which is completely covered by his collar. When the camera angle changes the knot is much higher and the rope is fully visible, although the horse hasn't moved yet. (00:01:35)NancyFelix
Continuity mistake: In long shots of the town when the movie begins, the town is on different banks of the river in different shots.
Revealing mistake: During the explanation of security procedures on the paddlewheeler there is a modern ceiling fan in the backround. (01:21:00)