Visible crew/equipment: When Mulder and Scully enter the abandoned mine through a doorway, the viewer can see at right in the distance a number of people sitting on a wall, and one crouching in front of the wall with what looks like a dog. They are sitting still, but there is still movement there. (00:16:00)
Continuity mistake: Up until Green No More in Series 2 (where the Green Ranger powers are destroyed), the Green Ranger's overshield constantly changes between solid-looking metal to flimsy-looking cotton. This is the most obvious difference between the Japanese and US footage.
Character mistake: Trivette hands the man in yellow a bullet recovered from the plane Walker and Alex were traveling on, which was shot down by an assassin flying a P-51 Mustang. This man, and later Trivette, mistakenly refer to the round as a "50mm," when in reality, Mustangs were equipped with M2 Browning .50 Caliber (12.7 mm) machine guns. (00:30:25)
Continuity mistake: In an interior shot of the detectives' vehicle, the car is a late 80s Chrysler (LeBaron or K-Car), obvious from the 'pentastar' logo on the steering wheel and the distinctive gauge layout. When the detectives walk away from the car, it is the homicide standard issue Chevrolet Cavalier.
Visible crew/equipment: Matthew is talking to Hank in the saloon about Hank's horse that Brian wants. After Hank agrees to let Brian work for him to pay for the horse, Matthew walks out of the saloon. The camera pans to the left slightly and a microphone can be seen moving behind Hanks head. (00:32:30)
Other mistake: Jack follows J. Edison Nash to a wine warehouse and watches as Nash punches numbers on a keypad in order to gain entrance to a private room. Nash punches the 6 and a beep is heard. He then punches the 8 and another beep is heard. During a close-up of Jack, four more beeps are heard, for a total of six. Jack says the number out loud - 862, which is only three digits.
Revealing mistake: There are numerous times throughout the series where the supposed big city of Metropolis is actually just a back lot set and none of the buildings are more than a couple of storeys high. Quite often the green hills of Southern California can be seen beyond the set and between the buildings.
Continuity mistake: In an earlier season Caine takes a young Peter to a place in the temple and explains that his mother is buried there. However in the series finale he shows adult Peter a picture that someone took months ago and Caine tells Peter that the woman is his mother and he's going to find her.
Plot hole: "Showdown": Darien's lost hat and jacket reappear without explanation after Kane finds him wandering in the desert. Also unexplained is how Kane conveniently happens to be leading an extra, unnecessary horse - unnecessary, at least, until he stumbles across the stranded Darien. (00:15:00)
Continuity mistake: When Filburt first reads his fortune cookie, it says "Bad luck and misfortune will infest your pathetic soul for all eternity". But later on when he is walking down the street it says "Bad luck and extreme misfortune will infest your pathetic soul for all eternity". (00:03:25 - 00:04:25)
Other mistake: When Butt-head is purchasing the pork rinds from the vending machine, he notes that the selection for them is F2. When he is pressing the buttons to dispense them, he presses the F button twice, but never the 2 button. Somehow, the machine still dispenses the correct item.