Revealing mistake: The sheets tying Billy's wrists to the bed aren't tight enough to keep him bound.
Revealing mistake: The robber who kills Billy's mother is shown cutting her throat but with the flat side of the blade. Moreover real blood doesn't ooze out so thickly, indicating it was makeup.
Character mistake: Andy speaks of Billy changing in the two months after he was hired when he was hired in the spring months ago.
Revealing mistake: When Billy smashes through the door of Linnea Quigley's house it's obviously made of cardboard.
Plot hole: Billy's not tall enough to impale Linnea Quigley on deer antlers.
Suggested correction: The movie blatantly shows Billy lifting her high enough above his head to impale her. It's literally right there in the scene. Additionally Linnea Quigley talks about the making of the scene in the documentary "In Search of Darkness Part II," and talks about the actor living her high above his head over and over while making the scene.