Continuity mistake: When Lana is hit by the axe, it hits her horizontally, but in the shot of her corpse, it is shown vertically.
Continuity mistake: In the film Demon is in the outhouse and is sitting on the bowl when it begins to shake. The toilet paper changes amounts on the roll between shots. (00:53:00)
Continuity mistake: The sound that startles Lana was breaking of plates. But when she investigates, she finds the cat sniffing fallen pots. (00:34:40 - 00:35:50)
Other mistake: After noticing that Tina is dead, Eddie fearfully backs away and leans against the tree. You can see Roy put the leather up and over the tree. This is impossible. He would have to whip it around the tree, not over it.
Visible crew/equipment: As Pete walks off into the woods, the cameraman's shadow is briefly visible on his back. (00:23:50)
Continuity mistake: When Violet is dancing in her room, Jason starts to walk up to her and we see the knife has dried blood on it. Then he picks her up, stabs her takes the knife out and now the knife is clean. (01:04:55)
Revealing mistake: When Tommy is about to slice Roy's arm, you can see that he is not really holding the machete in his hand. (01:19:20)
Continuity mistake: Lana smears lipstick on her upper right lip, but when she turns at the cat's noise, it is pressed and perfect-looking. (00:34:40)
Continuity mistake: When Jake gets a cleaver smacked in his face, you see him get slashed across his face. When Robin goes to bed and she sees his dead body, you can see the slash on his face is in the opposite direction. (01:01:15 - 01:03:30)
Plot hole: When Robin goes to bed you can see that Jake is not there. When she turns over Roy couldn't possibly have put Jake there in that short time without her noticing, not to mention that she was still awake. (01:03:30)