Deliberate mistake: In the beginning, when the two black workers are using the handcart, they bend their arms as they crouch down to give the illusion that they are slipping into the quicksand. (00:06:30)
Audio problem: When Hedley shoots a man for chewing gum on line the sound effect of his body hitting the ground takes place about a full second before he actually collapses. (00:11:50 - 01:11:45)
Continuity mistake: The scene where the gang stampedes through Rockridge, a thug on horseback lassos a man who is dragged down with the rope slipping down around his feet. As he's dragged foot first through the mud, he says "Well, that's the end of this suit" only now, the rope is up around his chest and under his arms and he's being pulled in a head first direction. (00:14:25)
Continuity mistake: When Mongo first comes into town and the man on the horse says "You can't park that animal here," Mongo punches the horse and its rider, and the horse falls. Before the cut to the close up of the man (obviously the stunt double), his head is facing toward the horse's head. After the cut to the close up of the man, his body is facing the opposite direction. (00:46:30)
Continuity mistake: When Mongo gets the "candygram", he closes his eyes BEFORE it explodes in his face. True, that is necessary for safety, but if he would have tilted his head just a little more, his hat would have blocked the view of his eyes. (00:48:15)
Revealing mistake: When Mongo wakes up and breaks free of the chains, in the shot where he breaks free, the chains suddenly shift position and some even disappear. This is because the camera was stopped and the chains were replaced with fake break always before the camera was restarted. Another way to see this is because the water that dripping down Mongo's face suddenly stops. (01:02:15)
Continuity mistake: When the crook kicks the door on a building in the fake town it falls over, but the same building falls over again when the dynamite goes off. (01:21:25)
Audio problem: Towards the end when everyone is running around the studio lot fighting, there's a tour group getting ready to enter the cafeteria. The tour guide's mouth doesn't even remotely match what she is saying. (01:26:10)
Visible crew/equipment: In the beginning when the two black workers are using the handcart to look for quicksand, you can see the cable pulling them in one quick shot.
Continuity mistake: When Sheriff Bart and The Waco Kid are sitting in the sheriff's office, the Waco Kid is shaving. He has shaving cream on his face, he wipes some if it off, leaving some on. Bart kicks a chair and the Waco Kid jumps up and the shaving cream is gone.
Revealing mistake: As Mongo enters the bar, you can tell the background is a piece of scenery just outside the entrance; there is a wrinkle in the fabric at the floor.