Continuity mistake: "11 Days to Zero": A saboteur on an overhead scaffold hastily sprays an X on the top of Nelson's car with white paint. In later aerial shots, the X is composed of 2 perfectly straight, thick lines stretching from corner to corner of the car's roof. No way was that X made in a few seconds with a spray can. (00:03:00)
Factual error: "Invaders": The ship's doctor claims that carbon 14 dating proves the man from the undersea capsule to be 20 million years old. Not likely. Carbon 14 testing can date once-living matter only within the last 70,000 years, and is generally considered accurate only within the last 50,000. (00:23:00)
Deliberate mistake: "The X-Factor": When the helicopter is chasing Nelson's car, re-used footage from a first season show briefly turns the otherwise color episode black and white. (00:24:00)
Deliberate mistake: "The X-Factor": Car-wreck stock footage turns the admiral's 1965 sedan into a much shorter, fatter 1950s model when it bursts into flames and rolls down the embankment. (00:26:00)
Continuity mistake: Throughout seasons 2-4: When the series went to color in the second season, the Seaview was redesigned with only one set of observation windows. But stock footage of the old multiple windows continued to appear for the rest of the series, usually with the film dyed blue.
The City Beneath the Sea - S1-E2
Revealing mistake: When Seaview's crew recover the diver's body in the beginning and clear seaweed from his mask, the "dead" man is blinking. (00:01:20)
The City Beneath the Sea - S1-E2
Continuity mistake: Seaview's windows form 8 horizontal rectangles in 2 rows across its bow. But the interior sets have windows that form vertical rectangles, and they're much closer together than they are in the exterior shots. (00:02:30)
The City Beneath the Sea - S1-E2
Revealing mistake: On the beach, Molina is petite, thin and small-chested in her wetsuit. Underwater, she mysteriously gains several pounds, bigger muscles and a much larger bust, thanks to a poorly-matched stunt double. (00:12:00)
The City Beneath the Sea - S1-E2
Continuity mistake: Seaview is on the ocean floor investigating the underwater city. Two inserted stock shots then show it up near the surface at periscope depth. In the next shot, though, it's back on the bottom again. (00:43:15)
Factual error: Crane clears an Air Force jet to land at the Antarctic ice station. But the station is located on a completely snow-covered sheet of ice with no runways. How and where could it possibly land? (00:27:30)
Character mistake: The General picks up the comms microphone and starts wrongly speaking into the back of it. (00:01:00 - 00:01:55)
Factual error: The diving bell descends to 4000 feet, where no light can penetrate and the ocean around them should be pitch black. But some strange, unseen phenomenon is lighting up the bell quite nicely for the camera. (00:21:15)
Deliberate mistake: Several of the roaming dinosaur segments here are repeated 2-3 times over. They're all recycled footage from producer Irwin Allen's own 1960 remake of "The Lost World," and Allen must have wanted to get as much use out of the dino shots as possible. (00:28:00)
Other mistake: One of the natives putting the captured Seaview personnel into the cave is wearing laced up sneakers. (00:36:25)
Other mistake: Aside from the error of having mines so densely packed and so close to the bottom so deep, there is no possible way the Seaview could have settled to the bottom while passing through this minefield without being destroyed. (00:48:00)
Revealing mistake: Crane overcomes his guard in a fistfight by hitting him in the face three times. But if you watch closely, it's apparent that not one of his blows connects. He "strikes" the air above the man's head all three times. (00:32:00)
No Way Out - S1-E12
Continuity mistake: When Victor tries to get into sickbay, the guard stops him, pointing a rifle at his chest. But in the very next reverse angle shot, the rifle is again in its original position in the guard's hands, pointing at the ceiling. (00:35:10)
No Way Out - S1-E12
Factual error: Victor is crawling around through Seaview's incredibly roomy ventilation ducts, pursued by several crewmen. But the air conditioning that's fluttering little ribbons on all the vent covers isn't, for some reason, disturbing a hair on any of their heads. (00:44:25)
No Way Out - S1-E12
Continuity mistake: When Anna tries to kill Koslow, Victor spies on her from behind the ventilation grate. The ribbons fluttering on the duct cover disappear when the shot switches to Victor's point of view. (00:46:50)
Revealing mistake: One of the saboteurs sneaking into the palace keeps looking up at someone off camera. He's not watching the door he just entered by, so who's he looking at in what should be an empty corner of the room? (00:00:30)
