Continuity mistake: The ground is dry and clear throughout the entire episode in all exterior scenes, until the snow covered ground in the background when Duncan is driving to Ellen's house about 2/3 through the episode.
Paul Is Dead - S1-E6
Factual error: The female British astronaut is in her space suit. There is a supposedly British flag on her left sleeve. But the flag is wrong. The red diagonal stripes are centered on the white field. They should be off-centered by 3/5 of the white space. Not centered. This is a common mistake you find in British flags bought outside the UK.
Continuity mistake: When Mary offers Walter the fast food bag of chicken soup, her hand disappears and reappears on the top of the bag. (00:34:40)
Factual error: Thomas holds the Gendarmerie rank of Capitaine (by which he is frequently addressed by his subordinates), and thus should wear three horizontal silver bars on his epaulettes. However, in the only scene where his rank is displayed he instead wears the two chevrons of an ordinary gendarme.
Factual error: A British soldier in 1940 says he was educated at the University of Warwick. The university wasn't founded until 1965.
Continuity mistake: Throughout the series, the Barbers pull their cars straight up their driveway. But the cars are nearly always shown coming back down the driveway driving forward.
Continuity mistake: When Irina meets XIII on the river dock, she leaves her car, closes the driver side door and walks to XIII. Moments later, when XIII is shot, she runs back to her car, where the door is wide open.
Factual error: The DI refers to the local policeman as "Officer" Fuller. No British police officer would use this term to refer to another British police officer. She'd have said Constable Fuller or PC Fuller.
Continuity mistake: When the hostages try to get some rubble to catch fire, they find that everything is covered in some flame retardant stuff. Yet, in the very first episode one of the very first things they do is to make a small fire to get the fire alarm going.
Factual error: Captain Carrillo is target shooting with a hand weapon. She empties the magazine, but she catches the magazine and hands it to her ranger partner instead of letting the empty magazine fall to the ground. As a trained military officer and training with special operators, catching an empty magazine is an extremely bad habit and practice, which is a big no-no. (00:40:23)
The Tyrant - S1-E11
Continuity mistake: After being knocked unconscious by the gorilla soldier, Janor's arms move from being at his side in the close ups to outstretched in the long shots.
Continuity mistake: When Nick's mom tells him to show Gypsy around she takes the cigarette away from her lips. A shot later it's back in.
Episode One - S1-E1
Factual error: In the fairground chase the characters jump over some Heras fencing that wasn't invented until the next decade.
Containment - S1-E5
Continuity mistake: At the end of the episode, when the bad guy is preparing the syringe of small pox, he follows the usual method of tapping out any air in the tube - when he is shown injecting himself, a large air bubble is back in the syringe (which would probably kill him quicker than the smallpox).
The Planet of Dr. Moreau - S1-E4
Other mistake: When the mountain starts to collapse, the Silver Surfer and the enslaved trolls begin falling to the ground below at a rate comparable to what the falling rate on Earth would be. The Surfer is able to catch himself on a ledge and absorb his restraining collar into himself, granting him control over his powers, which he uses to prevent the trolls from falling to their deaths. With the amount of time the Surfer spent struggling to overcome his restraining collar, the trolls would have already fallen to the ground.
Continuity mistake: When the bomb under the bus is being defused, it's counting down and beeping once every second. We see the timer at 0:45, then cut to the face of the woman defusing it - counting the beeps when we cut back it should be on 0:45, but it's jumped up to 1:06. Camera pans down to her face, then back to the bomb, and it's now on 0:43, but going by the beeps it should be on 0:36. We cut away again for 5 more beeps, cut back and the bomb's only just ticking onto 0:41.
Factual error: Possibly a mistake from the novel on which the series is based, but although he later became Bishop of Hereford, St Thomas Cantilupe wasn't baptised in Herefordshire. He came from Buckinghamshire.
Continuity mistake: As Dave is leaning over the edge of the air boat with Rose behind him, he pulls a chunk of metal out of the water and places it on the edge of the boat on his left side. When he gets up from his lying position moments later, the metal is gone. Moments later again, with an overhead shot of the boat, we see what appears to be that piece of metal positioned at what would have been his right side, not his left. This is also where we see him step over the seat (twice!) in subsequent camera angles. (00:30:00)
The Losers - S1-E4
Visible crew/equipment: When Lodgepoole is telling Marshall about how the Bureau of Lost caused the Great Depression, someone's arm becomes visible in the upper left corner of the screen. (00:12:51)
Continuity mistake: When the bad guys create a roadblock with their 2 cars as Hopper drives his girlfriend to her mother's house, the cars stop with one on one side of the yellow line, and the other stops with the steering wheel over the line. The camera angle changes, and now both cars are neatly, evenly positioned, with their engines sitting over the line. (00:02:05)