Continuity mistake: At the beginning, The main character is driving a car and hits a bicyclist and kills him. The inside shots from the car show the driver's window closed. The outside shots show the driver's window open.
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.
The Four of Us are Dying - S1-E13
Revealing mistake: As the men walk out of the alley, the block continues ahead of them. You can see it's a painted background.
Continuity mistake: After McNulty freezes the office, a co-worker is getting water from a faucet, and the water is frozen in motion, but right before McNulty unfreezes the office, a female co-worker is in the background at the faucet with no water coming out of the faucet.
The Mirror - S3-E6
Visible crew/equipment: Clemente walks over to the portrait of the former ruler, and throws his glass. Just as he completes the action, the camera looks at the portrait. There is a movement of what appears to be a device on the right side of the shot firing the glass.
The Four of Us are Dying - S1-E13
Visible crew/equipment: As Arch Hammer is walking to Hotel Real, the camera is looking up towards him as he walks. Just before he turns to go in, the lights, roof, and support beams of the soundstage are above the skyline backdrop.
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.
Factual error: The lieutenant is wearing cavalry insignia, but he is in the infantry company.
No Time Like the Past - S4-E10
Factual error: The U-boat has a spinning sonar mast. Subs in 1915 didn't have that.
A Hundred Yards over the Rim - S2-E23
Factual error: Although set in 1847, Christian Horn is carrying a rifle made in 1884.
The Rip Van Winkle Caper - S2-E24
Revealing mistake: The suspension machines are nothing more than large terrariums, there doesn't seem to be any electronics or piping or machinery of any kind attached to them.
Of Late I Think of Cliffordville - S4-E14
Other mistake: Miss Devlin tells Feathersmith the cost of his trip, including the historically accurate maintenance of the town Cliffordville and its citizens, but line doesn't make any sense, the town is not a recreation since Feathersmith is being literally sent back in to time, the town can't be anything other than accurate.
Of Late I Think of Cliffordville - S4-E14
Factual error: Even though its supposed to be 1910, the banker's daughter plays a 1960's Steinway piano.
Other mistake: When Martin Landau throws the mini tape player to the floor, you hear the fast forward chipmunk sound but the reels are still spinning at the same speed as before.
The Odyssey of Flight 33 - S2-E18
Character mistake: The real speed that was reported was 3,000 knots. At one point, the plane encountered a bright flash, and violent shaking. The Captain surmised that they broke the sound barrier. 3,000 knots equates to over 3,000mph. The sound barrier (Mach 1) is about 767mph, and the captain would know that.
A Thing About Machines - S2-E4
Revealing mistake: When the car is approaching the pool to push the man into the water, the tires tracks are visible in the grass, showing that the car had already made that trip. Either tracks from an earlier take, or the scene was filmed and then played in reverse, to be safe for the actor.
Continuity mistake: When Martin meets his parents in their house, the door is split and closes in the middle with a screen. In the next shot, it is a full door without a screen.
Suggested correction: As seen from the exterior, the outer door is a very wide screen door with its handle to the left and hinges at the right. Behind the screen door are two solid doors which swing open inward from the center. Notice the wide screen door is the door Martin bangs on when his father closes the solid double doors (with individual doorknobs), and later in the episode when Martin's mother walks outside we see her push open the screen door.
Of Late I Think of Cliffordville - S4-E14
Other mistake: Mr. Feathersmith sells the 1403 acres to Mr. Hecate for $40, so he can pay Devlin to send him back to his own time. $40 in 1910 would be about $1,127 today and it's extremely unlikely that anyone, especially a man like Hecate, would have that much money on them. (00:47:45)
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.