Revealing mistake: After Bella gets married and Jacob is angry because he thinks Edward will kill her, Sam tells the pack to leave. When the pack enters the woods, they jump down into what appears to be some sort of pit. You can see blue lights, slightly illuminating the pit area in the woods that Jacob and the pack jump down in. (00:39:00)
Continuity mistake: When Edward transforms Bella, he bites her neck first, then her arms, and so on. In the very next close up of Bella, there are no bite marks in her neck at all.