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 Running Death": During West and Gordon's poker game at the end, Gordon tilts the table by at least 30 degrees - and none of the poker chips, cards or cash moves an inch. Apparently, everything was glued down. (00:44:30)
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 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)
The Night of the Deadly Bed - S1-E2
Revealing mistake: The large casa on the hillside is an obvious photo superimposed on to the film.
The Night of the Deadly Bed - S1-E2
Revealing mistake: The explosive squib is visible on Artie's leather container just before Flory shoots it.
The Night of the Deadly Bed - S1-E2
Revealing mistake: The steel I-beam West uses to bust down the doors is made of wood as the wood grain is visible.
The Night of the Deadly Bed - S1-E2
Revealing mistake: Electrical sparks between the wheels and track rails are visible under the coal tender of West's train as it rolls, showing the train is an electric model.
The Night That Terror Stalked the Town - S1-E10
Revealing mistake: During the final scene where West and his double, Janus, are shooting at one another, the two look identical to one another. West goes to the roof and jumps off onto Janus who is by the cannon. However, the revealing mistake is the original looking Janus is playing the role of West diving off the roof, and the one who is fighting Robert Conrad who is supposed to be playing his double, Janus, is standing by the cannon. When the two begin to fight on the ground, one should not be able to tell the two apart, but it is apparent the faces are different. The mistake is fixed when the two get off the ground and now both fighters look like West.
The Night of the Human Trigger - S1-E12
Revealing mistake: In the next to last scene of this episode during the Sawtooth earthquake, while boulders are falling and trees are being uprooted, West, Gordon, and Faith are not struggling to keep their balance so as not to fall, they are just motionless standing - something that cannot happen with such a strong earthquake. The camera, which is shaking, attempts to make it look as if the three are shaking with the earthquake.
The Night of the Human Trigger - S1-E12
Revealing mistake: In the opening earthquake scene right before the freeze frames appear, West and Gordon are in the bar. The glasses and pitcher on the bar by the bartender, the bottles of liquor behind the bartender, the bottle on top of the piano, and the ashtrays on two tables never move out of place, even though other tables have broken, chairs have toppled, the ceiling is destroyed, and the support beam falls. It is obvious the camera is doing the shaking, not the ground.
The Night of the Puppeteer - S1-E21
Revealing mistake: Just before she dances away, the life-size ballerina "puppet" fails to hold her fixed stare and blinks. (00:20:00)
The Night of the Puppeteer - S1-E21
Revealing mistake: Zachariah Skull's bald head has a problem. The latex skull-cap used to cover the actor's hair keeps bubbling and wrinkling as he speaks. (00:43:00)
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 the Burning Diamond - S1-E26
Revealing mistake: In the fight scene before the second freeze frame during the fight scene, the splicing of the film is off because we see the stationary West shifting a few inches as Midas appears and disappears on the staircase in front of him.
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 Sudden Plague - S1-E28
Revealing mistake: In the opening scene in the saloon when Gordon takes the glass from the motionless bartender's left hand, the bartender's right hand keeps slightly moving the bottle.
The Night of the Eccentrics - S2-E1
Revealing mistake: Tony throws two knives at West - but on the wall where the knives hit, the rectangular openings from which the blades actually emerge are delineated beforehand. Happens again a few scenes later, where slots cut in the door are already there before the knives are thrown. [Spoiler: It's inconsequential to the "revealing" error, but if you play the scene in slow motion, you can see that both times, the knives pop through from the back of the "wall." This is also how the carnival trick is performed.] (00:17:05)
The Night of the Eccentrics - S2-E1
Revealing mistake: Two scenes after the opening credits, West fights the strongman Titan. When Titan throws West (who is horizontally positioned on Titan's shoulders) down to the ground through the circus tent, a mattress upon which West lands is mistakenly exposed.