Factual error: Right at the start of the episode there is a sign visible on the side of a building that shows the German word "Warenhaus." This is a wrong translation of the English word "warehouse." The correct German word should be "Lagerhaus."
Factual error: Doug and Tony time travel to one million years B.C., where they encounter dinosaurs. Not likely. All the dinosaurs were rendered extinct several million years earlier by an asteroid strike. There weren't any left by 1-million BC. (00:29:45)
Revealing mistake: When Tony and Doug are captured by the Greeks, the lead Greek soldier points his sword to Troy. The "Troy" shown is a modern still picture of the ruins of the Greek Acropolis and surrounding structures, complete with a modern blue and white vehicle that looks like a bus in the lower left hand part of the picture.
Continuity mistake: Sgt. Isugi turns his head slightly right and down to acknowledge Tony's injury, but the next shot of Isugi shows his head straight forward, addressing Doug.
The Revenge of Robin Hood - S1-E16
Character mistake: When Robin Hood and his gang ambushes the king's cavalry, one of his crack archers fumbles and drops an arrow as he is about to shoot.
The Revenge of Robin Hood - S1-E16
Other mistake: As the King's guards prepare to torture Doug and the Earl of Huntington with red-hot irons, one of them is handling the irons without gloves or any other non-conductive material to prevent his hands from being fried.
Factual error: The Gestapo major's office has a picture of Rudolf Hess hanging on the wall. Not likely, as Hess parachuted into Scotland in 1941 and was considered a traitor to the Third Reich.
Continuity mistake: At the very end of this episode, when they have just arrived in the new time, Doug is fighting a man in a turban. He loses the turban, but then the next shot, it has reappeared on his head. (00:48:54)
Factual error: When Doug and Tony recount the causes of the Trojan War, they mention three Roman goddesses - Venus, Juno, and Minerva - instead of using their Greek names - Aphrodite, Hera, and Athena.
Continuity mistake: The distance between Ulysses and Epeios goes from distant to close together as the shots change.
Factual error: The battle scenes show the Greek and Trojan cavalry troopers equipped with stirrups on their saddles. The stirrup would not be used until nearly 1,400 years later.
Revealing mistake: After Tony stabs Wogan with the sword, there is no blood on the blade when Tony pulls it out.
Continuity mistake: In the dungeon where Merlin reminds Doug and Tony they are from the future, Arthur's hands instantly move from by his sides to holding the collar of his tunic.
Continuity mistake: When Arthur has the standoff between himself and Doug and Tony, Doug is standing abreast of Tony in the frontal shots and slightly behind him in the views from the rear angles.
Revealing mistake: As Merlin circles the frozen Doug and Tony in the Time Tunnel, Tony blinks.
Audio problem: At one point during Doug and Tony's hand to hand combat with the Union soldiers, the traditional Hollywood sound of a fist smack to the face is heard as Tony blocks a blow with his arm, instead of the sound of a thud.
Continuity mistake: When Tony begins fighting the Union soldier, Tony kicks the soldier's musket out of his hands and it lands to the right. The next overhead shot now shows the musket landed behind the soldier as Tony picks it up to fight another soldier.
Continuity mistake: While Doug is sword fighting with Michaels, Doug knocks off a three-candled candle holder off the table, but the next cut shows it back on the table.
Continuity mistake: When the major hands Doug the musket, Doug is holding it with his right hand, but the next shot shows Doug holding it in front of him with both hands.
Revealing mistake: A modern, mid-20th century concrete bridge/walkway is visible in the background of the Union soldier before he shoots Corporal Perkins.