Continuity mistake: The pole that impales Deborah moves from going though her chest just below her boobs, to much lower down, in her waist between shots. (00:31:55)
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: When Deborah is impaled with a post in the tent, the amount of blood on Luke's face decreases between shots. (00:32:00)
Continuity mistake: When Diana walks out of the doors carrying a silver tray, you can see inside the tray and it is completely empty. However in the following shots as she walks across the car park, there is now a white bowl of dog food inside the previously empty tray. (00:32:20)
Continuity mistake: The position of Edna's headscarf changes between shots before her head is slammed in the car door. (00:34:55)
Revealing mistake: When Edna's head is slammed in the door, it is completely bloodless and her head appears to bounce back to normal shape. (00:34:55)
Character mistake: In the scene where they show Jason's mailbox, it says Vorhees. The correct spelling is Voorhees. (00:35:00)
Continuity mistake: When Phil, who is possessed by Jason, has Josh tried up inside the Voorhees house, he takes some shaving cream and puts it all over Josh's moustache. However in the next shot there is suddenly much more cream on Josh's moustache/chin. (00:35:45)
Revealing mistake: Phil, who is possessed by Jason, puts shaving cream on Josh's moustache. Then, he takes a razor and begins to shave his stubble off, and then his moustache - however, you can quite clearly see that Josh's moustache is not there anyway, and has disappeared between shots. (00:36:00)
Continuity mistake: After Jessica shoots Josh in the head, he lies on the floor and his tee-shirt is clearly untucked. But when he grabs Jessica, and then wrestle on the floor, his shirt is now tucked in. (00:38:00)
Continuity mistake: When Josh is attacking Steven, after Steven tried to save Diana from Josh, the small table with a lamp, photo frames and other ornaments on it has half it's items knocked off, with a couple of ornaments remaining on it. In the next shot, these ornaments have also gone. In addition, the green rocking chair next to the table, has a decorative cloth sitting on the seat of the chair, but in the next shot the cloth is draped over the back of the rocking chair. (00:38:45)
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)
Continuity mistake: When Steven impales Josh with the fireplace poker, Josh starts to stumble very slowly toward the window, but in the next shot, he is moving with enough force to move across the room and shatter through a window. (00:39:25)
Continuity mistake: When Josh is impaled by the poker, he stumbles towards the window and crashes out of it, pulling the white curtains with him so that they drape outside the window. But in the next shot the curtains are pulled back neatly inside the room once again. (00:39:30)
Continuity mistake: When Josh attacks Diana, Steven tries to save her. We see Steven being taken by the police and his blue jeans are spotless. Yet in the very next scene of Steven talking with Randy at the station, Steven's jeans are now soaked in blood, for no apparent reason. (00:40:35)
Continuity mistake: When Vicki is cleaning the bloodstain from the carpet, Jessica enters the room and they talk. Between shots the yellow rubber gloves and the small sponges which sit on the bloodstained carpet change position. (00:41:30)
Visible crew/equipment: When Jessica enters the living room, and Vicki is cleaning the bloodstain, you can see a boom mike pole in the top right corner by the ceiling fan. (00:41:35)
Continuity mistake: In the police station, Jessica gives a rubber duck to Stephanie in one shot, but in the next shot it has gone. It returns in the following shot. (00:43:55)
Continuity mistake: When Josh transfers the Voorhees creature into Robert's mouth, blood runs down Robert's right cheek as this transfer is made. Once Robert then wakes up as Jason, the bloodline has swapped cheeks. (00:56:40 - 00:58:00)
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)
Answer: Of course he would be reborn exactly like he was before he was blown apart. Which is why he needed a blood relative to do so.