The Night of the Bubbling Death - S3-E1
Revealing mistake: As West drags the body of a bad guy out of the scene, the supposedly unconscious man is holding his head up so as not to have his head dragged through the dirt. A truly unconscious person's head would flop back on to the ground.
The Night of the Brain - S2-E21
Revealing mistake: Mr. Braine screams as his steam-powered chair crashes into the bandstand. If you look closely at the next shot, just before the explosion, you can see that the dummy now in the chair has its head bowed forward. It also has light brown hair, rather than Mr. Braine's silver hair. (00:47:10)
The Night of the Doomsday Formula - S4-E2
Revealing mistake: When West rescues the doctor's daughter from the flames by swinging down from his rope, the face of the stuntman playing the daughter for this scene is obvious.
The Night of the Camera - S4-E10
Revealing mistake: As Bosley Cranston fights the bad guy, Pat Paulsen's stunt double does not look like Paulsen - the stunt double is much younger looking.
The Night of the Brain - S2-E21
Revealing mistake: When Gordon is looking outside on their train car platform, it is obvious the background desert scrub is a painted scenery flat.
The Night of Miguelito's Revenge - S4-E12
Revealing mistake: An obvious dummy floats out of the underwater coffin after West pops open the top of the coffin.
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)
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)
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)
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)
The Night of the Big Blast - S2-E4
Revealing mistake: It is obviously a dummy body that West and Gordon net, then drag behind the carriage before the dummy body explodes.
The Night of the Bubbling Death - S3-E1
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)
The Night of the Big Blast - S2-E4
Revealing mistake: The "corpse" Miklos wheels into Dr. Faustina's laboratory is pretty healthy for a dead guy: you can see his chest moving up and down as he breathes. (00:27:00)
The Night of the Big Blast - S2-E4
Revealing mistake: During the sword fight on the stairs, Artemus' stunt double's face is in plain view in several shots. (00:30:00)
The Night of the Murderous Spring - S1-E27
Revealing mistake: Kitten bends apart the cell bars, allowing West and Gordon to escape. But when they brush against it on the way out, one of the "iron" bars gives, flexing like the rubber that it probably is. (00:40:30)
The Night of the Burning Diamond - S1-E26
Revealing mistake: Artemus is sampling beef stroganoff from a pot on the stove. He then carries the kettle by its swinging handle across the room, tilting it just enough to reveal to the camera that it's really empty. (00:43:10)
The Night of Miguelito's Revenge - S4-E12
Revealing mistake: At the beginning of the episode, as Jim West walks away from the newsstand vendor and closes the magazine, a 1967 ad for DieHard batteries ("The DieHard Fights the Common Cold") can be seen on the right-hand page of the prop magazine, in a modern sans serif font.
The Night of the Janus - S4-E18
Revealing mistake: About half way through this episode, the hooded man West is chasing goes through double doors and closes them. West slams his body to open the doors. He steps back to ram his body into the doors again to force them open. Before he does, we see the doors sort of slightly move back and forth (this looks very odd and unnatural) before West slams them open.
The Night of the Pelican - S4-E13
Revealing mistake: Towards the end of the episode when rocket one is fired, it launches very, very slowly with little force/velocity - obviously a prop.
The Night of the Raven - S2-E3
Revealing mistake: When the marshal opens the train's rear door and comes in to arrest Lana, you can see wrinkles in the "sky" outside. It's really a painted cloth backdrop. (00:48:40)