Near the end of the movie when Martin and Mr. drive up to the beer stop and find the girl with the crossbow, there is a New York license plate on the front of the black Chevy pickup truck. When Martin and the girl leave the next morning the license plate is gone.
When Martin chases Cooper (his dog) outside at the beginning of the movie the rain starts and stops in some shots.
Martin's shirt changes from having light stripes to having dark stripes during the movie.(Although he might have turned his shirt inside out occasionally, since it's his only shirt)
37:15: Martin is sewing up a cut on Mister's left bicep. 37:42-37:50: there's no sign of a cut or sutures on Mister's left bicep.
When the group ambush The Brotherhood, Belle is seen wearing a long white cotton shirt. In the next scene, they enter a lock-down town called Strivington, where Belle buys the shirt after seeing it in a store window.
Early in the movie, they stop next to a cornfield. Late in the movie they run through a cornfield. These cornfields had to have been planted long after the vampire epidemic. Seems rather unlikely that anyone was out planting entire fields of corn when everyone was struggling merely to survive.
Late in the movie, they run through a green corn field which would indicate summer, and in the next scene, the trees have no leaves as if it were fall or winter.