Continuity mistake: When Jack is aboard the boat at the end of the film, the dragon drops a rock into the water. The water splashes into the boat soaking everyone. The front of Princess Elane's dress is wet, but in the next couple of shots it is completely dry.
Continuity mistake: After Cormoran has smashed down the portcullis and drawbridge, he is received by crossbowmen and spear-throwers firing from the battlements. As he rips off one of the drawbridge's chains to fight back, the shadow inside the archway behind him suddenly becomes noticeably darker.