The Night of the Inferno - S1-E1
Revealing mistake: When Liddy's mansion explodes and burns, the switch from real house to cardboard model is very obvious. (00:35:15)
Continuity mistake: "Night of the Arrow": West and Gordon leave two champagne bottles and four glasses sitting on the table when they walk away to answer the door. When they return, the bottles and glasses have all completely changed positions by themselves. (00:41:30)
Continuity mistake: "Night of the Arrow": President Grant's cigar keeps getting longer, shorter, and longer again as he gives West and Gordon their special assignment aboard the train. (00:08:10)
Continuity mistake: "Night of the Bubbling Death": When Grigsby first approaches the stolen U.S. Constitution, it's under glass (we can see the light reflections). But seconds later he lifts the paper without removing the glass, which has disappeared. It's back later, when West must cut it to retrieve the document. (00:09:10 - 00:36:30)
Revealing mistake: "Night of the Jack of Diamonds": During his fight with West, Sordo the bandito, who has a gray beard, is suddenly several years younger with a dark brown beard, thanks to the substitution of a stunt double. (00:35:30)
The Night of the Brain - S2-E21
Other mistake: Throughout this episode Gordon keeps producing orange-sized smoke bombs, but he has no pockets in his clothing large enough for all of them and if he did, the size of the bombs would be obvious in his clothing.
The Night of Miguelito's Revenge - S4-E12
Continuity mistake: The barber chair West sits in has dark wood arm rests, yet the close up of his hand as he is being chloroformed by Loveless shows white arm rests.
The Night of the Man-Eating House - S2-E12
Visible crew/equipment: When the old man gets up from his chair and moves toward the door, the camera shadow is moving on the wall behind him. (00:18:40)
The Night of the Underground Terror - S3-E19
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)
The Night of the Howling Light - S1-E14
Continuity mistake: It's night outside the train's windows - until Artemus looks out at the attacking Indians; then it's day, and in next shot, it's night again. (00:06:55)
The Night of the Howling Light - S1-E14
Continuity mistake: Akima dies with his head tilted to the left. In the next shot, he's managed, even though he's "departed," to tilt his head to the right instead. (00:49:20)
Revealing mistake: "Night of the Bubbling Death": Artemus takes off his coat and is wearing smoke canisters strapped to his back underneath. But the close fit of his jacket in previous shots reveals that the device wasn't there until just before he began removing the coat. (00:43:15)
Continuity mistake: "Night of the Arrow": When Artemus pours the president a drink, the glass is only 1/4 full. When Grant picks it up, however, it's suddenly 3/4 full. (00:09:15)
Revealing mistake: "Night of the Underground Terror": During the climactic fight scene, James West's famously tight trousers rip apart in the crotch, amply revealing his very 20th-century white jockey briefs. A few shots later, that rip mends itself and the pants are split (much more decorously) down the right outer seam instead. (00:46:00)
Factual error: "Night of the Lord of Limbo": At the end, Vautrain tells West and Gordon to go through the door on their right. The door is on the camera's right, but is on West's and Gordon's left. (00:45:10)
The Night of the Turncoat - S3-E13
Visible crew/equipment: As West is swimming in the water tank that is filled with dangerous sea creatures (Hammerhead sharks, etc.) a modern day (1960's) frogman is swimming behind West in the tank.
The Night of the Skulls - S2-E13
Revealing mistake: In the livery stable fight scene between Gordon and Tigo, the tines of the pitchfork Tigo threatens Gordon with wobble, indicating they are made of rubber or a soft material and not metal.
The Night of the Gruesome Games - S4-E5
Revealing mistake: Just before Doctor Raker gets to the cliff before falling, there is a jet airliner seen in the sky just over his right shoulder.
The Night of the Underground Terror - S3-E19
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.
The Night of the Amnesiac - S3-E22
Continuity mistake: As Gordon interrogates Crotty, Crotty raises his cigar to his face twice.