Continuity mistake: Theseus stabs Hyperion in the throat and blood immediately fills his mouth and runs out the corners. After the camera flashes back from Theseus' expression there is no blood in Hyperion's mouth or trace on his face. When his head falls to the ground his mouth area is again covered with blood. (01:36:45)
Other mistake: Theseus spends a whole minute swinging his axe at the log with absolutely no effect. (00:06:50 - 00:07:55)
Continuity mistake: In the shot where Hyperion is walking through the ranks of his army it first shows his army holding their swords with their left hands, but as the shot changes to the front all the troops are holding their swords with their right hands but in exactly the same combat stance. (01:18:25)