Continuity mistake: After sounding the "alert" for his guests, Raden turns around to fully face them, and as he addresses the Reverend, from the back his hand is gripping the arm of the chair. In the the next moment, there is a frontal shot, and Raden's hands are folded on his lap.
Showdown with Rance McGrew - S3-E20
Continuity mistake: The car Rance drives onto the set can be seen in the street from inside the saloon, but disappears when Rance, in character, comes through the swinging doors. It's visible again in the very next shot, but vanishes anew when Jesse James comes through the doors, after which it yet again reappears in the very next shot. (00:04:30 - 00:07:20)
Showdown with Rance McGrew - S3-E20
Continuity mistake: The saloon's windows are much narrower inside than they are on the outside. (00:17:20)
Showdown with Rance McGrew - S3-E20
Continuity mistake: Rance McGrew's white horse is tied up with its head just a few inches from the hitching rail, but a moment later is untied and several feet away from the rail. Next shot, it's tied up close again, though no one's touched it. Finally, it's completely loose, and at the episode's end, is wandering into the street. (00:22:00 - 00:23:30)
Showdown with Rance McGrew - S3-E20
Factual error: Throughout this episode, the TV western supposedly being filmed lacks several essential elements. There are no clapboards to mark the scenes; the modern-day car is constantly in shot through the swinging doors; and the set is located inside the "real" saloon when it should be on a sound stage.
Audio problem: The keys we see being depressed on the player piano never bear any resemblance to the actual notes we hear. (00:13:00)
The Last Rites of Jeff Myrtlebank - S3-E23
Continuity mistake: An entire piece of toast disappears off of Pa's plate from one shot to the next. (00:08:40)
The Last Rites of Jeff Myrtlebank - S3-E23
Continuity mistake: Jeff corners Orgram behind a tree with a tire swing hanging from it and punches him to the ground. But in the next shot, Orgram is still on the ground and the tree and tire swing are nowhere in sight. (00:17:35)
Other mistake: Chambers asks what time it is on Earth, a strangely vague question to which the Kanamits grant an equally odd answer: on Earth, it is noon. It can't be noon everywhere on Earth at once. While it can be fancifully explained away ("They somehow knew to answer for the time zone he was taken from"), it still jars the viewer, because neither Chambers nor the aliens, both highly intelligent, should make this sort of imprecise mistake. Both director Richard Bare and Damon Knight, author of the original short story, confirmed this as a scriptwriting error that should have been caught before shooting began. (00:02:15)
Revealing mistake: Stock footage used here is far too obviously borrowed from several old movies. While the episode is set in the 60s, people's clothing and all the cars are noticeably many years out of date. (00:03:05)
Factual error: Author Damon Knight was happy with Rod Serling's TV adaptation of his short story - except for the change that allowed the humans to translate the Kanamit language as though it were a code. Said Knight, "Without some sort of interplanetary Rosetta Stone, deciphering an unknown language would be impossible." (00:22:10)
Factual error: As well as the obvious problem with translating an unknown language as if it was a code, there is no chance that the word "serve" would have the same double meaning in English and Kanamit. It would be like the word "dope" and its French equivalent meaning "idiot" and "illegal drugs" in both languages.
Other mistake: The Kanamit have to lower their heads to pass through the doorways on their own ship.
Suggested correction: Just as astronauts on the International Space Station and the Shuttle before that had to.
Other mistake: Old Ben duplicates Jenny so she can accompany him to his home planet. As he can turn into anything, he should be able to approximate her height. When the now twins walk out, the girl on the right is a couple of inches taller than the girl on the left. Not only that, but her hair is noticeably darker.
Audio problem: For reasons unknown, the child's voice throughout this episode is played by an adult actress trying to sound childlike - and the unconvincing imitation is painfully obvious. (00:19:25)
Continuity mistake: During Rod Serling's opening narration you can see over his shoulder part of the outline of the portal to the 4th dimension, which would be drawn there later in the story.
Continuity mistake: The hundreds of ropes used by the tiny people to pull down Craig's statue vanish in the next shot, when the statue hits the ground. (00:23:55)
Hocus-Pocus and Frisby - S3-E30
Visible crew/equipment: When Frisby tells the two travellers that they're looking at the grandad of the American automobile, we can see the reflection of a crewmember wearing a suit, possibly the director, who stands up from a directors chair (also seen in a following shot). Then as Frisby tries to locate the gas tank, the shadow of the moving boom mic is visible on the store's doors. (00:06:20)
Hocus-Pocus and Frisby - S3-E30
Visible crew/equipment: After the two travellers have paid for their gas, when Frisby advises them to check in someplace because of the clouds, the reflection of the moving boom pole and mic can be seen above the word "shop" on the store window. (00:08:00)
Hocus-Pocus and Frisby - S3-E30
Revealing mistake: Make-up for the space aliens was apparently changed after the closing scene in the store was shot and before any footage of the aliens' "true appearance" was actually taken. This resulted in Frisby, who is now telling the truth and finding no one to believe him, saying that the aliens had a single eye in their foreheads, when in fact, the aliens each had two eyes, in the traditional location. (00:24:00)