Plot hole: When Jamal saves Knolty's life and is invited into his home, he leaves his work jacket at the lake shore. This jacket is where he kept his spray-paint. However, later in the movie Jamal has somehow recovered his spray-pain.
Continuity mistake: At the final battle, when Percy is holding a knife on Victoria's neck, you can see that is right under her chin. When he cuts her neck, the cut is lower than the place where he held the knife.
Continuity mistake: After Jamal saves Knolty's life, Knolty is sitting up on the ground. In a shot from behind him, his arms are holding him up, however when it switches to a shot from his front, his arm appears on his chest though only a split second later.
Factual error: In the 14th century, Normandy was an enemy of Britain's. There is no way a Duke from Normandy would marry an English princess.
Continuity mistake: When they're closing the portcullis as Jamal is escaping, when the guard is struck, the last horizontal beam is shoulder level, with the spikes much lower. When the camera changes angle, the gate has risen so the spikes are nearly above his head and Jamal is no longer as crouched down to get under.
Continuity mistake: After Jamal receives lordship, there is a scene where he is conducting a meeting with the other lords. When he first walks in, there is a pocket on the upper left side of his shirt. In the next shot of him, the pocket is gone, revealing his "Sky" logo. Then in the next shot, it's back on again, and in this instance he makes a show of ripping off the pocket to reveal the logo.