Continuity mistake: Sean is standing by a window when Ray throws a chain through it and the chain wraps around Sean's neck. The following scene has Sean being pulled through the window, breaking away all the glass and the wooden dividers. When the scene cuts to the outside and the kids looking at Sean being pulled away, two broken wooden window sections have managed to regenerate and are visible from both the right and left sides of the window frame.
Continuity mistake: Tammy slips in the blood, landing on her back and right side. She is wearing a tight white long sleeved shirt and she ends up with a large blood stain that takes up about 3/4 of the back of her shirt. Tammy looks for a way to get out of the garage and when the scenes cut to shots of Tammy from behind, the blood stain on the back of her shirt change from alot, to little, to alot, back to just a little, and then to having the whole right back side covered in blood.