Continuity mistake: In the opening scene young Cal has scrapes on his face after he misses the roof jumping with his bike, in the next scene when he finds his mother dead his face has no scrapes, and then in following scene he is running and has scrapes on his face again.
Continuity mistake: Immediately after giving the order to burn the village which hid the prince, the assassins attacked. In subsequent scenes, it appears that the village had already been burned to the ground, even though the guards were otherwise occupied, and only moments had passed.
After escaping from execution, the assassins still made use of throwing knives out of their garments as they ran through the city. These would have been removed from them before they were shackled in the cell.