Revealing mistake: When Alice moves toward her window with the ice pick and the cat jumps in, it's obvious a crew member threw it in. (00:10:40)
Revealing mistake: Just after the scene where Mark is killed, there's a shot of Jason's feet as he opens a screen door and walks across a dusty hardwood floor. As the dolly pulls backward across the floor, you can see the camera's roller marks in the dust. (00:59:10)
Revealing mistake: When Jason slices Ginny's leg, not only can you see that a piece of her jeans has been pre-cut and simply just falls off revealing her flesh wound, but you can also see the outline of the tube pumping blood under her jeans. (01:02:20)
Revealing mistake: When Ginny has run out to her VW Bug and is attempting to start it, Jason is supposed to be back in the house just on his way out to get her. But if you look at Ginny sitting in the car, in the lefthand corner of the windshield you can see a reflection of the top of Jason's hood. He was there all the time, crouched down beside the fender just waiting for his cue to pop up. (01:07:45)
Revealing mistake: When Jason is on top of Ginny's car, she reacts to the pitchfork through the roof a second too early. (01:10:50)
Suggested correction: She had just seen Jason through the window before he disappeared. Then the pitchfork comes the roof. Just before she screams, you can hear the pitchfork tearing through the fabric of the roof. That's what's she's reacting to.
Also, when you see the car and Jason is reaching in through the hole in the roof from the passenger side, it's pretty obvious she would have seen him before he stuck the pitchfork through. That could be another reason she react before we see the pitchfork.
Revealing mistake: Notice when Jenny pees it's shown just pouring out. But she's lying flat and her jeans would obviously absorb most of it. But it just pours out like she's standing up with no jeans on. (01:14:30)
Revealing mistake: At the end of the film when Ginny and Paul are fighting Jason, his machete hits the shrine where his mother's head is displayed and where Terri's body is strewn. When the machete hits, Terri flinches, even though she is dead. (01:16:00)
Revealing mistake: When Jeff and Sandra are in the woods, they bend down to examine a mangled animal. You can see that the animal has human teeth, not animal teeth.
