Continuity mistake: When Beowulf is rescuing Pendra, at the end of the fight he is holding is sword over one of the men. In some shots it is clean, in others it has blood on it. (00:08:00)
Continuity mistake: When Karl is startled by the weaponsmaster and grabs for his weapon, the candles that are on the table change between shots. (00:22:15)
Audio problem: When Roland is urging the men to fight, the first one to attack is carrying a large mace that is seemingly made of metal. When Roland defeats him and the mace falls to the ground it sounds as if it is made of light wood. (00:20:25)
Revealing mistake: When Beowulf is fighting Grendel in the sanctuary and is climbing up into the rafters, his black support wire is visible. (00:44:10)