Visible crew/equipment: As Tina swerves off of the road after seeing her mum get killed by Jason in the middle of the road, if you look in the back of the car, you can see a camera set up, filming the shots in the back seat. (00:43:15)
Revealing mistake: When you see Jane pinned dead to the tree you can see her pulse. (00:19:15)
Continuity mistake: When Dan is in the woods the amount of wood he is carrying decreases. (00:25:35)
Revealing mistake: When facing Jason after he throws Melissa with an axe in her head, you can see that the eye holes on the mask he wears are covered with black cloths. (01:13:50)
Continuity mistake: When Tina uses her psychic power to hang Jason, the size of the hole he falls through changes between shots.
Continuity mistake: When the girl is thrown out the window you see her falling with her right shoulder first while crouching. In the next shot she falls directly onto her stomach. (01:02:05)
Continuity mistake: When Jason throws the girl out the window he throws her with her back first. When it cuts from the outside she is coming out the window face first. (01:02:00)
Other mistake: When Melissa opens the front door and Jason is standing there, he raises his right hand, holding an axe, and plunges it straight down. But when Melissa has the axe in her head it is on the opposite side and at a different angle than it should have been. (01:13:45)
Continuity mistake: In the scene Robin tells Maddy she's going to get David, a cup of coke on the counter vanishes for a shot, the green napkins move around, and the blue flowery pattern on the bowl disappears and reappears. (00:30:50)
Visible crew/equipment: When the girl is knocking on the door while saying "Maddy?" you can see several shadows from persons moving alongside the wall beside her, even though she is supposed to be alone there. (00:59:15)
Continuity mistake: When Michael goes to the bathroom in the woods, Jane is standing next to the road. In the reverse shot, she is standing next to a tree.
Continuity mistake: When Jason shoves his fist through Dan in the woods his fist is bloody, but when he kills Dan's girlfriend, the blood is gone. (00:27:00)
Revealing mistake: When the fireman picks up pieces of the hockey mask, the pieces are too thin and fragile to be a hockey mask. (01:20:40)
Continuity mistake: When Jason swings the girl in sleeping bag against the tree, he grabs the head end, yet the head end is the one that hits the tree. [This is fixed and not a mistake in the uncut editions (theatrical and new release dvd) because the uncut scene has Jason taking six swings with the sleeping bag against the tree, including the head end.] (00:26:50)
Continuity mistake: Just before Jane is killed in the woods, you see her standing with her arms crossed from the back. When it cuts in front of her she is crossing her arms again. (00:18:50)
Continuity mistake: When Tina battles with Jason, the height of the basement roof drastically differs.
Continuity mistake: The bullet hole that Sheriff Garris shot above Jason's eye in Friday the 13th Part VI: Jason Lives is missing from the mask in this movie. (00:14:30)
Continuity mistake: When Tina is driving, she swerves to avoid Jason. The trees that she almost hits change between shots. (00:43:15)
Continuity mistake: When David says "The neanderthal man...," he puts his right hand on the girl's chest. When it cuts back his arm is no longer there. (00:53:35)
Continuity mistake: When Robin tells Maddy that she's gonna stick with the deal and "have a good time" she opens her arms up twice between shots. (00:33:10)
Answer: Jason being afraid of water is not portrayed consistently throughout the series. Continuity between sequels was not a major concern when making this series.
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