Revealing mistake: When Jason (in Robert's body) is shot in the head at the end of the hall, a close up reveals the bullet hole to be obviously just makeup. (01:05:35)
Revealing mistake: If you watch closely, it is painfully obvious that in the beginning, when Jason is getting shot up, they are just repeating the same shot from different angles.
Other mistake: In the scene at the beginning where Phil eats Jason's Heart, you'll notice that he screams like a monster for a bit. Don't you think that the two security guards would easily hear the screaming and intervene, being that they're in the very next room? (00:13:40)
Continuity mistake: In the scene where Jessica is in the shower crying and the power goes out, she gets out, puts on a white t-shirt and goes walking around the house. When she walks through the garage door and grabs a hammer, there is blood on the front of the t-shirt (right at or a little lower than her waist and looks like someone grabbed the shirt with a bloody hand). Where did it come from? She didn't run into anything or anyone. [There's a deleted scene showing her step on a piece of glass. She gets blood on her hands when she pulls the glass out, then presumably wipes her hands on her shirt. Still a mistake, as removing that scene means the blood appears from nowhere, but there's the reason.]
Character mistake: In the scene where they show Jason's mailbox, it says Vorhees. The correct spelling is Voorhees. (00:35:00)
Revealing mistake: When the female FBI agent falls over the railing onto the table, you can see that the legs have been pre-bent to make it break easier. (00:04:50)
Continuity mistake: When the bomb is dropped, Jason is looking skyward, but in the next shot he's looking straight forward.
Factual error: When the FBI agents are shooting Jason, 2 things happen that shouldn't, 1. His machete is shot but doesn't move, the force from the bullet would cause the knife to move. 2. When the bullets hit the knife, they cause sparks, bullets never cause sparks when they hit metal.
Continuity mistake: There are two times after the female FBI agent gets out of the shower that she is wearing underwear when she put none on, and the pair that she has on is completely different from the one she originally took off. The first is when she runs directly to the door from the shower after the power goes out. The second is seen when she puts on only a towel shortly after, and then falls over the railing, you can see she's wearing underwear there as well. (00:04:45)
Revealing mistake: In the scene where Deborah and Luke are having sex in the tent, the coroner (as Jason) comes from behind her, stabs her, and brings the poker upward slicing her upper torso in half. If you look closely in normal play, or put in slow motion, you can see the body is already cut before the poker comes up. (00:32:00)
Continuity mistake: At the start of the film Jason chases Agent Marcus from the cabin, and she is barefoot. But in the shots of her running through the woods, in some shots she is barefoot, in others she has white socks and big black boots on, and in others she has flesh-coloured trainers on. (00:05:10)
Continuity mistake: When Jason is attacking Steven in Diana's house, before Steve impales Josh (who is possessed by Jason) with the the poker, Josh lifts his head to look into the mirror but the reflection of Jason stays still. (00:39:15)
Revealing mistake: Jessica is in the shower crying, and then she grabs a shirt and pulls it on, never putting on anything else. However after Steven punches Robert, he carries Jessica to his car. As he puts her down on the seat, Jessica's shirt rides up, revealing a flesh-coloured thong. (00:58:45 - 01:00:40)