Revealing mistake: Early in the opening scene, Barbara and her brother Johnny are going to put flowers on their father's grave. As the two of them approach the gravesite, with Barbara leading the way around a low cut bush (centre screen), the camera angle changes and suddenly their positions in their walk have unrealistically changed. After Barbara says, "There it is," the camera angle changes and we now see Johnny walking behind the bush in a spot he had already walked (so he walks a small patch of lawn twice). Barbara instantaneously changes from walking full stride with her hands in her coat pocket to a momentary standing position with legs apart and the beginning of an initial step. Her hands are now no longer in her pockets but swinging at her side.
Revealing mistake: When Ben goes outside to "take care of" the first two ghouls and has them on the grass, you can plainly tell that he's not actually hitting them (with a tire iron) but is striking the ground next to them. Also, the sound being made is of hitting dirt, not a human being.
Revealing mistake: As soon as Ben fires the first shot from the rifle you can plainly see it's a fake. Not so much from the look of it, but by the fact that there's no kick back whatsoever. The bullets you see him loading it with look big enough to give a pretty good blast. Even a .22 caliber would have more kick than what he's using. His rifle shoots like a BB gun. (00:45:35 - 01:28:30)
Answer: No. Each is a progression of several weeks or years.
Captain Defenestrator