Best fantasy movie mistakes of 2010
Continuity mistake: After being chased by soldiers after talking to his uncle, Dastan gets into a swordfight with Garsiv. As soon as it starts, Garsiv hits a pillar with his weapon knocking a significantly large chunk and a another smaller chunk out of it. In the immediate shot, the size and locations of the two chunks differ.
Continuity mistake: Just before Flynn cuts off Rapunzel's hair, there is a shot from behind him and he reaches up with his right hand to push her hair behind her ear. His arm is visible up to his forearm and the shackle is nowhere in sight. However, in the next, wide shot, the shackle is suddenly up around his wrist.
Plot hole: When Astrid gets on Toothless for the first time, Toothless takes off uncontrollably and tries to scare her. Hiccup seems to have no control over him at this time. How is that so if with the new tail fin, Toothless cannot fly without Hiccup's precise control of the tail fin? That whole sequence would have fallen apart. This mistake was even admitted to on the DVD Commentary.
Continuity mistake: When Abby slaughters the bullies, we see most of the scene from Owen's underwater point of view. First, a decapitated head floats down, leaving a trail of blood. Then, more dismembered bodies splash into the water. We get the sense that the pool water around Owen should be pretty bloody. Yet, when he surfaces, the water around him is completely clear, with no evidence of any blood or bodies.