Blooper

(at around 1h 16 mins) Clyde's motorbike was apparently found after he's been "missing" but unless Gus were to have actually cleaned it and gotten his scarf all untangled, his bike would've been found a bloody mess.

Zowie's fur changes color several times after he returns from the Indian burial ground.

When Drew is bringing Zowie up to the burial grounds, Zowie looks gray and black instead of mostly white as seen in the previous scene.

When Gus comes back with the body bag and shovel to pick up Clyde's body, Clyde's one good eye is open and staring up vacantly. But when Gus rolls Clyde over onto the body bag, his eye is now closed. It's open again when Gus goes to zip up the body bag.

(at around 1h 30 mins) There is much more brain splatter on Jeff's face the second time he approaches the door (this time, holding the ax).

Feral kittens that are young, without any human interactions for the last couple of months, would be very skittish and running away from people every chance they got. Tiger and her siblings act as if they've been well socialized the entire time.

Yolander tells Chase of the Creed cat. Church was hit by a truck and ended up on Jud Crandall's lawn. He states that he sent a sample of blood to be analyzed. Lewis never took the cat to the vet, except when he took him to get fixed and Church was very much alive. Lewis ended up burying Church and later administering the lethal dose to kill him.

The other doctor claims the dogs blood cells were completely deteriorated, as he was dead. If that were true the blood drawn would have been black, or at least very dark red, but it was bright red when it was taken out.

At Renee's funeral, Gus introduces himself to Chase, and identifies himself as " Town Sheriff ". Towns don't have sheriffs. He should have said that he was the sheriff of Kennebago County.

The movie places Ludlow, Maine in Kennebago County. No such county exists in Maine, and the real town of Ludlow is in Aroostook County.

(at around 49 mins) When Gus is being buried by Jeff and Drew, he winces twice when the dirt hits his face, although he's supposedly dead.

During the opening, Renee kneels into a pool of dirty water. Seconds later, after the director yells cut (because of the missed fx cue), she walks off set with a dry, pristine, clean costume.

The casket is too small for a woman.

When the Matthews' move into their new home, there is a box of clothes labeled "Geoff". But, in the credits, the character's name is spelled "Jeff".

When the kittens are found killed by Zowie, they are in a cage slightly above his, but when Zowie first saw them, they were in a cage across the way.

Gus electrifies the metal cage of the rabbit hutch, presumably to prevent predators, including Zowie, from breaking into the hutch and killing his rabbits. It is quite evident that the hutch is so full of rabbits, that they are touching the metal, and yet remain unscathed from the electric running through it.

When Clyde is hovering over Geoff after scaring him in the cemetery.

When Drew comes home near dawn after burying Gus, his angry mother is waiting at the kitchen table with a coffee. The shadow of a person passes on the wall across the table from her, but no one else was present in the home.

Clyde Parker is brought back to life after being buried. But it is already established that for the resurrection to take place, a person needs to be buried by one of their own, meaning by one of their close family. Clyde was buried by Gus, who is unrelated to him, so he shouldn't come back to life at all.

Drew tells Jeff that Gus Gilbert is his stepfather but when his mother punishes him for skipping school, she calls him Drew Gilbert. A stepson would never take the last name of his stepfather, only the mother by marriage.