(at around 40 mins) When the Sheriff is shot during the ambush scene, it is seen that his face is in Zombie makeup. However, when he falls down from the shot, it's clear that his face is normal.
(at around 32 mins) When Ben is cut down from the noose of the hanging post you can clearly see his tongue when the priest is over him. Yet earlier in the movie it is explained that Ben had eaten his own tongue.
(at around 21 mins) When Elmer and Luke take turns shooting at a tin can, the can is a modern version. Tin cans from that era would not have "beading" - the ridges that ring a modern can to give the shape strength and stability.