The Night of the Fugitives - S4-E7
Revealing mistake: Ross Martin's stunt double is obvious after Hallelujah Harry's coach begins exploding. The stunt man looks nothing like Martin and has an obvious bald spot on his head, whereas Martin did not.
The Night of the Kraken - S4-E6
Continuity mistake: When Jose' Aguila pulls down the net, he is in front of the bar. The next shot he is instantly punching a bad guy in front of a window, which is several yards from where he was at the bar.
The Night of the Kraken - S4-E6
Continuity mistake: During the bar fight, Aguila and the goons he is fighting disappear from the scene, showing only West fighting some bad guys. Instantly Aguila appears in the exact same area where West was fighting.
The Night of the Kraken - S4-E6
Other mistake: While walking on the waterfront after the bar fight, West and Aguila's clothes are dry where moments before they dove out a window into the ocean.
The Night of the Kraken - S4-E6
Continuity mistake: While struggling under water with the kraken, West surfaces, then the next shot shows West deep underwater and breaking the surface again.
The Night of the Gruesome Games - S4-E5
Revealing mistake: The guide wire of the knife Dr. Raker throws at West is visible, as is the hole in the wall where the knife point lands.
The Night of the Gruesome Games - S4-E5
Visible crew/equipment: A film crew member's shadow is visible to the left in the scene of West getting his horse back on its feet.
The Night of the Kraken - S4-E6
Revealing mistake: Bubbles from the underwater camera crew are visible as West swims wearing the experimental diving gear.
The Night of the Kraken - S4-E6
Revealing mistake: The strings controlling the kraken's tentacles are visible as it attacks West and Aguila.
The Night of the Camera - S4-E10
Continuity mistake: When West finds the half poker chip, he moves to place it in his left outside vest pocket with his left hand, but the next shot shows him placing the chip into the inside left pocket of the vest with his right hand.
The Night of the Plague - S4-E24
Other mistake: In the last fight scene, West runs uphill from the cave entering the scene from the most east side of the screen. There is a bad guy on the ground to West's right side as West is running uphill. The villains chase West, but their shot shows them entering the same scene from the middle of the screen with the guy on the ground on their left side.
The Night of the Pelican - S4-E13
Deliberate mistake: After Jeremy Pike drops the box in front of the firing squad and it begins to emit smoke, the wind blows the smoke to the right. The actors playing the soldiers in the firing squad then move themselves into the smoke and begin coughing and choking from it.
The Night of the Kraken - S4-E6
Factual error: West and Artie are trying to move a cabinet from the wall. A closeup shot shows West's left hand entering from the right side of the shot to press a button that allows a secret panel to open. Unless West twisted his left hand 180°, then him pressing the button as shown is not possible.