Factual error: When Roy is electrocuted and falls from the roof, after Karen uses the defibrillator paddles on Roy, she lifts both paddles, looks at the EKG monitor and says "He's converted." How exactly could Karen have known that he's converted? It's impossible for the EKG monitor to show anything at all. Either the defib paddles have to be in contact with Roy's body for the "quick-look" to get a reading, which they weren't, or the ECG electrode discs have to be on Roy's chest connecting him to the EKG monitor, and they weren't. As an aside, just watching Marco having problems attaching the air mask, and quickly glancing up towards the camera frustrated, then giving up is priceless.
Visible crew/equipment: In the opening scene where General Clayton is explaining the 4077 to the psychiatrist, the scene changes to the outdoor set and the camera pans to the right. As the camera pans past the hospital, a white 1970s era shuttle van can be seen driving into the set in the upper right corner of the screen. (00:01:35)
Visible crew/equipment: At the mill, when John tells Buck that Willie Brimmer might be at the Montgomery cabin with Jim-Bob, in the next closeup of John we see a billowy trail of cigarette smoke at the bottom right corner of the screen, but the only people standing there are Elizabeth, John, and Buck, and none are smoking. Presumably, it was someone offscreen smoking too close to the camera (similar to a mistake in 1978's "Halloween"). (00:26:05)
With This Ring, I Thee Kill! - S1-E7
Factual error: Rhodes views the silent movie and the film breaks, leaving the last frame frozen on the screen. Wouldn't happen. When 16mm film broke in 1970s projectors, any portion that jammed in the mechanism was exposed to intense heat from the projection lamp, and would burn. (00:35:30)
El traje del tío Jacinto - S2-E16
Visible crew/equipment: In the credits, there's a unknown person hiding behind Don Ramón (Raymond).
Continuity mistake: As Banacek approaches the room in the farmhouse that has the cross, he has a cigar in his mouth. As he enters, the cigar is gone.
Visible crew/equipment: As the old Indian sets fire to burn his dead son, he walks towards Cain and on the left you see a fire extinguisher. (00:10:04)
Factual error: 14/11/2013: Amy sails to Ireland from a ferryport in Yorkshire. Ferries to Ireland do not sail from any port in Yorkshire. Yorkshire only has coastline on the North Sea, on the east side of Great Britain, not the Irish Sea, on the west. A ferry from Yorkshire would have to sail right round the country to get to Ireland. We know they're still in Yorkshire, as the paramedics who are called have "Yorkshire Ambulance" on their jackets.