When the brothers get to the cabin, they are attacked by a
zombie, who bites Denton in the left shoulder. This wound disappears in the next shot of him struggling with the zombie, and remains missing until Jake shoots it.
When Jake and Denton first pull up to Alex taking off her waders, she is sitting on the back of her vehicle taking them off her left foot and throwing them to the ground. However, when they start talking to her and the camera goes back to a shot of her, she is once again taking them off her left foot and throwing them to the ground.
When Jake and Denton stop to talk to Alex on the way to pick up the abandoned truck, she warns them to watch out for hunters. But when the brothers are walking in the woods you can see new growth on the deciduous trees, indicating that it's early spring. Hunting is not allowed in the springtime in Vermont.