Chapter 6, being pursued by Wolfe's gang, Jim tosses a keg of powder into their path and explodes it, but after the smoke clears you can see a whole keg.
Chapter 1, Tombstone's horse keeps disappearing and reappearing when tied to the stagecoach. Also he is seen following the stagecoach not tied, then he is tied.
During chase scenes, when the action is proceeding from left to right, most shooters are right-handed. But when action is shown as proceeding from right to left, everybody is left-handed, including placement of their holsters.
Chapter 11, in the fight in the cave, Jim Benton jumps out to strike one of the outlaws with his gun, butt forward, then next shot, the gun is no longer seen, as he jumps on the outlaw and the fight begins.
Chapter 2, during the wild horse stampede you can see some wranglers in the distance.
Chapter 8 "Forward" states; "Wolf, Butch, and two others are in pursuit of Jim". Only Wolf and Butch are after Jim. No one else.
The amount of henchmen in Wolf's gang never diminishes when any of them are killed. The same five outlaws in his gang are shown throughout the whole movie.
In chapter 4, while Mary and Jim are riding away from the outlaws, Mary says "they are gaining on us". She somehow knows this without looking back over her shoulder.
The wagons are supposedly filled with ore yet there's plenty of room for Johnson's men to hide and then stand up.
At the beginning of chapter 7, one of Wolf's men is shooting at the explosives near Jim's men. Jim gets up from behind a boulder to get away, and the boulder wobbles.
Tombstone's rifle has a endless supply of bullets. It never seems to empty.
When Mary and Tombstone jump from the runaway stage coach they land without any forward movement as if they were jumping from a stationary platform.
Chapter 11, Jim and Tombstone enter the stable and discover the owner dead. Jim even tells Tombstone; "He's dead Tomb!" Suddenly two of Wolf Reade's henchmen pop out from behind the stable door and the dead owner suddenly jumps up and attacks Jim. The dead stable owner somehow turns into a live henchman.
Opening Sequences: singing doesn't match lip movements.
Chapter 11 one of the crew can be seen crouched down in front of the hay pile in the stable right before the fight.
Chapter 8, the boom mic shadow is visible behind Butch during indoor scenes.
Borax shoots his pistol like he's swinging a racket.
In Chapter 15 when Benton and his men halt the stage the shotgun rider doesn't bother to lift his gun, even though he does not know the intent of the riders.
Jim Benton pulls up to the hitching post and instead of wrapping the rein around it just kind of drops it over it.
Chapter 3: After realizing that they have been fooled by the bullets that had been thrown into the bonfire, they walk up to the fire right after a couple more rounds go off. They had no way of knowing if there were any more live rounds in the fire.