Continuity mistake: When Valerie's father was the werewolf, his right paw was burnt. Then, when we see the hand later, there isn't a scratch on it, but again later, we see that it is, once again, looking burnt.
Factual error: The forge in the blacksmith shop uses modern spiral ducting going up to the roof. The spring steel spiral wouldn't have been available, much less the plastic cover, in the period portrayed.
Factual error: The character Peter has a modern haircut that would not have been found during medieval Europe; his hair defying gravity despite being a time without hair gel.