Continuity mistake: When Jason crashes through the cabin wall and slashes the teen, a crate on Jason's right foot alternates from being on / off between shots.
Revealing mistake: At the final battle scene where Freddy and Jason, Freddy knocks over a bucket of spikes that land on Jason. Right before he does that they show a close up shot of Jason and you can very see normal skin of the actor Ken Kirzinger right underneath his left eye.
Plot hole: Right before the second boy gets killed he wakes up after having a dream of Freddy and sees his dad sitting next to him. When the boy taps his dad lightly his head falls off and we then see Jason standing there. In order for this to have happened, Jason would have had to unbutton the dad's shirt, chop his head off, put it back in place, and rebutton his shirt without getting any blood anywhere on the body and without the dad putting up a fight. Also Jason waits until after the boy wakes up and sees his dad dead before killing him. Wouldn't Jason just kill him in his sleep like he does to the girl in the cornfield later on in the movie?
Suggested correction: Maybe Jason set up the dad to freak out Blake. His dad left him on the porch and we don't see Jason actually kill him.
But this is not the way how Jason works - he doesn't play games as Freddy does; the moment he sees the person, he just kills. Killing of Blake and his dad was way off Jason's Modus Operandi.
Revealing mistake: In the scene were Freddy and Jason are fighting at the end, when Freddy puts the machete in Jason you can easily see a rip in the shirt made for the machete to go in.
Revealing mistake: In the cabin fight scene while Jason is trying to free his machete from the table, Kia picks up a wrench and starts hitting him. When she hits him across the face, you can see the wrench bend in her hand.
Audio problem: About fifteen minutes into the movie, when Gibb says, "I am so under the limit, Lori," her lips don't match the line.
Continuity mistake: When the three girls are sitting outside the school, Gibb puts her cigarette to her lips twice.
Continuity mistake: The end of Jason's machete changes throughout the whole movie. Sometimes it has a rounded end, sometimes it has a pointed end and so on.
Revealing mistake: When Freddy is about to kill Gibb, the claw near the top right that is in the locker bends like rubber.
Character mistake: There was no chance of Will and Lori knowing what's happening with Mark in the house. Neither him nor anyone else called them. So what made them rush home with van, after they've been casually driving in their previous scene?
Continuity mistake: At the end, Jason tears off Freddy's arm but when they go flying into the lake you can see Freddy has both arms intact.
Revealing mistake: When Jason sends Kia's body flying into the tree during the fight scene at Crystal Lake, you can see the dummy's arm go flying off of the dummy, in the upward direction, in the shot after the body makes contact with the tree.
Revealing mistake: Notice when Jason is stabbing Trey. Jason isn't even close to Trey at all. He's just stabbing the mattress.
Revealing mistake: When Freddy drops the large boiler on top of Jason during their fight in the warehouse, the boiler is made of cardboard or some other lightweight material because it doesn't land very hard and it even bounces a bit.
Suggested correction: It is also a dream which means anything can happen.
Freddy was trying to kill Jason. Why would he drop something on top of Jason that was too light to crush him?
Continuity mistake: Linderman accidentally shoots a Glock 17 in the van, grazing Will's right ear who grabs it, but during the remainder of the film there isn't a graze on his ear at all.
Revealing mistake: When Jason is whacking the party goers, you can see the padding Jason slices under their shirts.
Other mistake: Towards the end after the kids wreck the van, Kia points to a sign for Crystal Lake. That's where they are supposed to go but they go the other direction, away from Crystal Lake.
Suggested correction: They were still heading for the camp, which is where the fight takes place.
Revealing mistake: When Jason cuts off Freddy's arm you can see the actor has his arm tucked behind him under his sweater.
Other mistake: When the Hypnocil is shown on the Internet, the bottle says 1000 tablets. Considering they are big pills, there's no way that many could fit in the bottle.
Revealing mistake: When Jason swings his machete at Blake on the porch, as he swings you can see the actor stop swinging so it doesn't even make contact with Blake at all.
