Factual error: When Ulysses opens his mouth while speaking, modern dental fillings are in his teeth.
Continuity mistake: After prying off the lock to the storeroom with the pry bar, Doug drops it on the ground, but the next shot of him entering the storeroom shows it still in his hand.
Rendezvous with Yesterday - S1-E1
Character mistake: When Tony talks to captain of Titanic he states he was born in 1938, but in episode 4 "The Day the Sky Fell In" it is December 1941, he should be 3 years old, but as a young child he is about 12 years old.
Continuity mistake: Arthur ties a rope around the battlements and descends the tower's west wall. Tony then waves a torch to signal the soldiers to attack. He's standing at the same spot Arthur left from (the rope is still tied there), but in the long shot, his torch is waving from the tower's south wall instead of the west one. (00:41:15)
Factual error: The Vikings in this episode are fighting while wearing horned helmets. Contrary to popular belief, Vikings never wore horned helmets in battle. Some theories state the horned helmets were worn during special ceremonies, but never in battle or daily life.
Revealing mistake: Tony and Doug escape the torture chamber through a stone door that looks as thin as a piece of wood and freely moves when they use it to exit the chamber.
Continuity mistake: After the city of Jericho shows up on the screen, Dr. MacGregor is next to and above Dr. Swain, but the next cut shows her closer to Swain.
Continuity mistake: When Rahab approaches three soldiers, the second soldier places his hand on the arm of the first, but when the shot changes, it is now the third soldier with his hand on the second.
Revealing mistake: When the torturer throws himself against Tony, the stone wall buckles when he slams against it.
The Revenge of Robin Hood - S1-E16
Revealing mistake: The same crossbowman shown getting hit and falling off the wall twice does not merely drop his crossbow, but throws it away from him.
Visitors From Beyond the Stars - S1-E18
Factual error: Modern power cables are seen near Crawford's homestead, complete with aircraft warning flags draped over them. These cannot be mistaken for 19th century telegraph wires.
Visitors From Beyond the Stars - S1-E18
Revealing mistake: The view of the town seen through the saloon doors is a painted backdrop, as some of the actors cast shadows against it.
Revealing mistake: Doug throws a grenade at Nakamura that lands just a few inches from a pile of leaves. The leaves explode rather than the grenade, they're a cover for the pyrotechnics.
Revealing mistake: On the beach, Doug and Tony rest against a heavy boulder that wobbles when they touch it.
Visible crew/equipment: The shadow of a large light or camera equipment is visible on the beach sand as Nakamura takes cover behind a boulder.
Continuity mistake: A bush on the beach that was used to mask the pyrotechnics of the grenade thrown at Nakamura disappears when Nakamura starts walking towards Doug.
Continuity mistake: When Dr. Nakamura exchanges greetings with the Time Tunnel team, they are far apart, but the next shot shows all of them much closer together.
Continuity mistake: When Tony lobs the grenade at Lt. Nakamura, it lands at least a foot away from his right foot, but the next shot shows the grenade about three inches away.
Continuity mistake: Lt. Nakamura is shown kicking the grenade Tony threw at his feet, but the grenade disappears before he kicks it, Nakamura is instead kicking a mound of sand.
Continuity mistake: After Lt. Nakamura disarms Doug, Nakamura is pointing his pistol to the left at Tony, then the next shot shows Nakamura pointing the pistol at Doug.
