Even though New Moon (to most of us) was exactly what we expected and more, there still are mistakes here and there. Which is a common happening with all movies.
MovieMistakes.com outlines mistakes pointed out in various movies by moviegoers and their users. New Moon as of today has 33 mistakes in it. Here is a brief outline of what they have listed -
Bella’s bite mark scar is not in the position it should be, compared to where James actually bit her in Twilight.
When Jacob first shows off his tattoo, it is up at the top of his shoulder. Then when he is in the forest at the end with Bella and Edward, his tattoo is about 2 inches further down his arm.
During the breakup scene, you see a blue marker between Edwards feet in his wideshots.
After Bella awakes from the first nightmare, we see her Romeo and Juliet book on the pillow beside her. When Charlie brings in her presents the book is gone, but then reappears on the pillow between shots.
When Bella is at the cafeteria table with Mike, and he is asking her to a movie, her hair keeps moving from behind her ear to hanging in front, and back again.
When Bella and Edward enter the chamber with the Volturi, they change which sides they are holding hands on. This also happens when they leave, except it goes from arm on waist to hand holding
When Sam comes into the house and kisses his fiance, you can see the ripples in the edges of the plastic film used to put the tattoo on his arm.
In the very last scene, right before the ultimatum, if you look into the tail lights on Edward’s car you can see various members of the crew reflected.
You can check out the rest of the list here!
(Thanks to NewMoonMovie.org)