Continuity mistake: In the scene where Maddy hides from Jason, she is barefoot. In one shot she sees him, and bends down and grabs her shoes. In the next shot she picks them up once again. (00:49:00)
Visible crew/equipment: When Jason is walking down in the forest you can see three spotlights on the upper right. (01:02:55)
Continuity mistake: As Jason steps out of the puddle, his clothing is dripping wet. Then in the next shot as he walks after Tina, his clothes can be seen, dry. (01:10:50)
Continuity mistake: Tina's pink t-shirt that Mike notices by his feet, which fell out of her suitcase, is not actually there in the shot beforehand and simply appears. (00:09:10)
Visible crew/equipment: When Jason pushes Dr. Crews down the hill, as he's falling, you can see some kind of equipment attached to the back of his pants. (01:10:45)
Audio problem: When Jason pulls Russell's girlfriend underwater, you can hear her screaming as if she's still above the water. (00:37:50)
Continuity mistake: When Tina throws the plant at Jason it hits him in the chest. The next shot shows it hit him in the head.
Continuity mistake: In the shot where Sandra notices Russell's dead body lying on the shore, Sandra's trainers are lying right next to her shirt and shorts. In every other shot her trainers are nowhere to be seen on the shore. (00:35:50)
Visible crew/equipment: When the girl is looking for David in a dark room you can see the film crew member holding the microphone reflected in the window while he is moving it. (01:00:00)
Continuity mistake: When Tina opens the door for Nick, the fridge door has magnets, an organizer and a cloth on it. Later when Tina's mum closes the fridge door everything is now off the door except for a magnet. (00:17:00 - 00:31:15)
Revealing mistake: When Tina kills her father and the dock collapses, one of the logs hits the camera underwater. (00:06:40)
Continuity mistake: When Dr. Crews and Mrs. Shepard first arrive at the cabin, the bags/cases they carry change between shots. (00:08:15)
Continuity mistake: Robin's position changes when she is thrown out of the window.
Revealing mistake: Obvious stunt double for Tina as she drops the porch roof on Jason and when Jason grabs her and throws her onto the dock. Her hair becomes a smooth blonde wig.
Continuity mistake: The tent that Judy and her boyfriend are camping in changes size between shots.
Continuity mistake: Jason has on an entirely different outfit in this movie than in part 6. Since he was chained in the lake there would be no reason for his clothes to be different.
Revealing mistake: When Jason pulls the tent spike out of Jane's neck, her eyelids flutter. (00:19:20)
Continuity mistake: When Tina's mother takes out the video cassette she doesn't close the video cover. When it cuts to Crews entering, the cover is closed. (00:41:05)
Continuity mistake: In the prologue with the narration, you see the scene from six where lightning struck the pole to revive Jason. You also see Jason's tombstone shattering during the lightning strike. In six, you never saw the tombstone breaking.
Continuity mistake: As Tina is speeding away in the car after finding out that Crews wants her committed, she passes by a car that is supposedly the one belonging to Michael and his girlfriend. It is facing in the same direction as she is. If they were coming up to the place for the party, wouldn't their car be facing in the opposite direction, and on the opposite side of the road, which is where we saw it stop earlier in the film?
Answer: Jason was dead at the end of Part 6, the girl used her E.S.P. powers to bring him back to life.