Visible crew/equipment: In a scene in a cave that is the lair of the "eaters of the dead," the camera takes an overhead wide angle shot of the "eaters" walking down into the cave. It is possible to see a young man wearing a burgundy t-shirt and beige shorts (a crew member), sitting against the wall of the cave cross-legged.
Visible crew/equipment: As the Wendel leader approaches the village for the final battle, there is a closeup shot of him, on horseback, arm with weapon upraised. Look closely at his chest/underarm, and there is a plastic buckle (like a back-pack snap-in) visible holding the bearskin/costume. (01:21:15)
Revealing mistake: When the fireworm has descended upon the town and after Ahmed finds out the Wendol are human, you can see that he stabs the Wendol right through his side, not his chest.
Factual error: The clothing and most noticeably the armour of the Viking warriors is a very higgledy piggledy collection of dress from different places and times in history. Only Buliwyf actually seems to be wearing armour of Viking origin, some of the others have Spanish Conquistador armour and helms from centuries after the film is set and another wears a Roman gladiator's helm complete with face mask, another of the group is seen to be wearing a kilt (the redhead conveniently played by one of the two Scottish actors used as Vikings)which may well have been worn concurrently by their celtic neighbours but his kilt is quite modern in design.
Continuity mistake: When the Wendol are attacking the village at night, one of them is shot by an arrow and falls off his horse into water. A couple of minutes later the same shot of the Wendol falling is used again for another arrow hit.
Continuity mistake: Before the first battle scene, the king is telling them about the Wendel. The black-haired man is seen riding his horse back to the castle. He walks up and is seen taking off his gloves. There is a shot to the king and back to the black-haired man, and his gloves are on his hands.
Factual error: The Vikings follow the Norse religion, and make several references to it throughout the movie. But when waiting for the first Wendol attack, Herger states "The All-Father wove the skein of your life a long time ago". In Norse mythology, the All-Father (Odin) did not weave the skein of life, the Norns did.