Visible crew/equipment: The arm of the actual carriage driver is visible poking through the back of the carriage, slapping the horse and signaling it when to stop/proceed with a second set of reins, showing the actor in the carriage was not controlling the horse at all.
Factual error: At the mint, Arte hides in a broom closet. He carries nothing in (nor did he hide anything in there beforehand), yet he emerges later in an "old man" disguise, wearing a wig, hat, mustache, false nose, glasses and janitor costume. Magic closet? (00:35:00)
Factual error: The small round table in West's railcar parlor has a flip-over top, with secret maps hidden on the underside. The wine decanter and glasses all stay attached when it flips. But impossibly, when West turns the tabletop back over at the end, there's a full cup of coffee sitting on it. (00:48:30)
Revealing mistake: West and Gordon burn a perfect circle (unlikely in and of itself) in the metal floor in order to break into the dungeon below. West punches the circle out with his fist, then grasps what should be white-hot edges with his bare hands before jumping through the opening. Even if wood it would still be too hot to touch. (00:32:00)
Continuity mistake: West has a different hairstyle as it is parted down the middle when he is fighting outside the Nugget Saloon. In the inside fight and throughout this episode, there is no part in his hair - with the only exception of this outside fight. (00:13:30)
Revealing mistake: After West shoots Major Hazard on the water tower, the falling stuntman lands on a safety cushion that is about a half foot below the ground surface. Further, the next scene cut shows Major Hazard being covered by the tower contents, but Hazard is now lying on the ground surface, not below it like the stuntman.
Revealing mistake: The final gun battle in town has a gunman in a tower shooting at West. The gunman's perch is enclosed on all four sides by a bannister, but when West returns fire, shooting the gunman out of the tower, the bannister in front of the gunman has disappeared, allowing the stuntman a clear path to fall out of it.