In Chapter 8, while the town is going nuts for a gold rush, a buckboard is shown leaving and dragging a man behind it. Seconds later, this same wagon is shown parked in the same spot.
Wades black shirt and black hat changes to a white shirt and white hat in Chapter: 12, then changes back to the black shirt and hat in Chapter: 13.
In Chapter 4, when the Indians are attacking the Munro ranch, the bearded ranch hand (Jay Wilsey) shoots one of the Indians; the Indian falls and hits the ground, and his wig falls off his head. This same Indian is shot again in Chapter 5, and this same scene is shown again when Wade shoots the Indian - the wig falls off.
In Chapter 8, when Wade is having a shootout with Steve Claggett (Al Bridge), the sound of gun shots is heard when no gun is fired.
In Chapter 11, during the fight between Wade and Doc, the railing breaks; a rope tied to the railing (so it doesn't fall below) can be seen.
In Chapter 13, an Indian fires an arrow at the sheriff. He clutches his shoulder and falls over--but no arrow is visible.
Near the end of Chapter: 6, beginning of Chapter: 7, when Wade throws the powder keg at the Indians, after the explosion, the keg is still intact on the left.