The Eye of the Beholder - S2-E6
Revealing mistake: In the episode, all the people are shown from the neck down to hide their faces (which at the end we see this is on another planet as they are alien looking). But as the first nurse seen in the episode walks to the window and turns around, even in shadow you can see that she is normal looking, that is, no prosthetic or make-up applied for the alien effect.
Continuity mistake: After Decker escapes from being held and heads back to his plane, he does not have his overcoat or scarf, and does not put them on when he starts his plane and climbs on board. When Major Wilson lets him go and he's taxiing away, in one shot he has the overcoat and scarf on, with no time to do so.
Factual error: The Southern Pacific train that almost hits Nan's car did not serve the part of the US she was supposed to be in.
King Nine Will Not Return - S2-E1
Factual error: Military personnel in the desert would not be wearing dark uniforms but a light khaki tan.
I Shot an Arrow into the Air - S1-E15
Other mistake: Corey sees a sign for Reno Nevada that is in the middle of nowhere, that can't be seen from the road in the distance. Who would see it?
Other mistake: Lt. Mueller's German accent drifts in and out.
Other mistake: As Trooper Franklin is shining his light on the side of the car showing the fingerprints, notice the front passenger's door. The key hole and the black painted rim of it is not covered by the fingerprint, or paint as it turns out to be. But regardless, it's not covered. (00:14:15)
Other mistake: When Ferris first arrives in the town the the church bell chimes seven times indicating it's 7 o'clock. Later the bells chime again but this time only four times indicating 4 o'clock. Surely he didn't walk around the empty town for 9 hours.
Suggested correction: Since the revelation of the episode is that Ferris is merely in a simulation, it stands to reason that they control how quickly time passes for him.
Revealing mistake: When the old lady touches the door handle right before getting cut by the knife she gets paint smeared on her hand from the door handle before being cut with the knife.
Plot hole: If Walter was indeed immortal from his deal with the devil then there was no reason for him to use the Escape Clause when he was sent to jail. Since he can't be killed by any means and nobody can harm him there would have been nothing to stop him from escaping the prison the moment his cell was opened.
Suggested correction: He may be immortal and not feel pain, but he isn't super-strong and can't walk through walls or people, so escaping wouldn't be trivial. That isn't to say it'd be impossible or even that hard, but this is a man who got centuries of perfect youth and health, and all he could think of to do were things that would kill a normal human (even though, again, he can't even feel pain.) He also confessed to murder to experience the electric chair, not considering that they wouldn't just let him walk away when he survived execution. He's a short-sighted, unimaginative moron, and that's probably why the devil chose him.
Suggested correction: Walter uses his Escape Clause because he doesn't want to live forever in a prison cell. Even if he could escape at some point, he's not willing to spend any time behind bars waiting.
King Nine Will Not Return - S2-E1
Factual error: The shape of the B-25's top gun turret is completely different from the turrets actually used on these bombers.
Factual error: In his opening narration, Rod Serling says that he is quoting Shakespeare's play Richard the Third. His quotation is actually from Richard the Second, also written by William Shakespeare.
A Most Unusual Camera - S2-E10
Plot hole: How did the brother know where his sister and her husband were located after he escaped and jimmied open their door? The couple was staying in a hotel and they acted like they hadn't seen him in quite a while when he appeared on the picture of him walking in the room. They said he couldn't possibly walk through the door because he's been in prison for a year already.
Nervous Man in a Four Dollar Room - S2-E3
Revealing mistake: When Jackie pulls the wardrobe from the wall and spins it around, The Mirror briefly reflects an area beyond where the set ends.
Revealing mistake: When the main character proclaims, ".the new Walter Bedeker!" you can see the frames are running back and forth. You can tell by looking at the window curtains behind him.
The Mind and the Matter - S2-E27
Visible crew/equipment: While Beechcroft talks to his boss in the men's room, the boom shadow moves across the wall at the upper right of the screen. (00:03:35)
Factual error: Caswell acts surprised at the sight of the lighter, but lighters were around in his time.
Suggested correction: The modern lighter, which use ferrocerium to create a spark, was developed in 1903. Caswell was from 1880. This would have been different then anything he would have seen.
Other mistake: Bemis is happy because he has enough time to read all he wants, but all the food would be poisoned by the radiation and and even if it wasn't, meat and fish it would spoil from not being refrigerated.
Revealing mistake: One of the actresses who is supposed to be playing a mannequin doesn't start to smile until the camera is on her.
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.