Part 1 takes place on Friday, June 13th in "Present Day." Mrs. Voorhees' tombstone says "Pamela Voorhees 1930-1979." But June 13, 1979 isn't a Friday. In Friday The 13th Part 3, Jason's hands looked like a normal man's, but in Part 4 (which takes place the next day), he has long black fingernails. In Friday The 13th Part 3 Jason was stabbed in the leg, but there is no blood stain or cut on his pants in Part 4. When the attendants are rolling Jason on a stretcher, his feet are not facing them, but when they come into the room with Axel, it appears that he has switched positions. When the nurse is leaving Axel in the morgue, the double doors swing open and he catches the right door, but the left door stays open with nobody holding it. EXPLANATION - In hospitals, double doors like that are on hinged mechanisms that keep both doors open for stretchers to come through. When Trish and her mom are jogging, a bush in front of them moves before they run by it. It looks like the cameraman brushed as he was walking backwards. When the group is walking to the lake they meet up with Tina and Terri (coming from the opposite direction). The group asks the twins which way to go, and they point in the same direction they had just come from, saying "That is where we're going." EXPLANATION - The twins changed their mind and just said that because they wanted to hang out with the other teenagers. Rob says when he first meets Tommy and Trish that he is hunting bear, and Tommy says that there are no bears in the area to discredit his story. However, Paul gives a long speech to all the counselors in Part 2 about bear safety, saying that bears are wandering all over the woods - even though Part 2 takes place only a few days before Final Chapter. EXPLANATION - Either Paul was trying to scare the counselors into staying at the camp in Part 2 or Tommy was mistaken. When Paul dances with Tina, she takes his cap and puts it on. A few shots later Paul has it back but he doesn't appear to have taken his arms off her shoulders while he was dancing. When the gang is going to the lake for the first time, they walk for a long time, so long that it ends up being a better idea to go back and get the car. When Samantha goes for a swim, it seems much closer. EXPLANATION - The first time they went they were going to a specific place, (supposedly for the rope swing and it being 'secluded' from other cabins). When Samantha goes out, she goes to the closest shore. In Samantha's death scene, Jason stabs her from beneath the inflatable boat she's lying in. Later, Paul swims out later and finds her dead body. If Jason had stabbed her through the bottom, shouldn't it have sunk? EXPLANATION - The bottom of the raft is not inflated, it is simply rubber stretched across, so it does not sink after being punctured. In the shot where Jason is lifting Paul into the air with the speargun, you can see the two wires lifting the actor into the air, even though the filmmakers tried to cover it up with fog. When Terri goes out and move her bike, we can hear the bike's kickstand being raised. But when Tina looks through the window, both bikes are up and it is doubtful that Jason would have set it back up after killing Terri. When Jimbo is killed you can clearly see that the clever going into his head has got a cut out of it so it will fit his head. When Doug is in the shower, his hair is completely slicked back, but in the shots from outside of the shower you can see through the frosted glass that his hair is "poofy" and hanging over his forehead. When Jason crushes Doug's head in the shower, Jason's mask has two red marks close to the nose. Later in the film, when Tommy and Trish fight Jason, those red marks are no longer there. When Tina gets thrown out of the window by Jason you see a top view of the car as she is falling. If you take a look at the car, you can see the car is already dented and the windows are already shattered before she lands. There's a bench in the second floor hall that is visible when Sara goes from the bathroom to the bedroom to dry her hair on the left wall. However, this same piece of furniture is later seen on the opposite wall in front of the banister railing when Jason chases Trish upstairs. Jason throws an axe through the door at Sara's head, but when she backs up the axe is firmly stuck in her lower abdomen. When Sara tries to escape from the house she is unable to open the locked front door. When Rob and Trish go to investigate, the front door is unlocked, and it doesn't seem like Jason did it. when Trish and Rob go into the house, they look right at the projector screen but don't react to Teddy's blood being all over it. Trish and Rob enter through the front door and immediately go to the basement. Then Rob fights with Jason in the basement and Trish tries to runs out the front door but finds Tina's body. If Jason was in the basement, there was really no time allowed for him to have put the body there. When Jason throws the hammer at Trish, it looks like it is just rigged to the wall and not actually embedded the way it should have been. When Jason is trying to get into Tommy's bedroom, the bookcase they use to barricade the door has some toys on it. If you look closely, you will see a yellow and white stuffed animal fall off the second shelf - but in the next shot it is back on the bookcase. When Tommy and Trish hide in Tommy's room, Tommy grabs a chair which is teetering in his hand - then suddenly it is on the floor in the next shot. There is also a purple monster mask hanging from Tommy's ceiling, and when Jason busts through the door, it begins to spin. A few shots later it is hanging still, but in the next shot it is once again spinning. When Trish is inching by Jason lying on the floor, in one shot she steps over his arm and her feet are near his shoulder, then in the next shot it shows her stepping over his arm again. When Trish picks up the TV, she accidentally knocks the lamp onto the ground. But when Trish and Tommy are coming out of the room after hitting Jason, you can see the lamp is standing up again in the background. When Gordon (the dog) jumps out the window in one shot he is breaking through glass, but in the next shot he is moving through the window, but there is no glass around him. Right before Trish jumps out of the window, you can clearly see in the moonlight both of Ted White's perfectly normal eyes staring at her. When Trish jumps out the window you can clearly see that she sinks into the ground (on a mattress or something hidden under the dirt) but when she stands up she is on solid ground. Jason crushes a lamp on the floor and the room becomes pitch dark but a moment later it is lit again by a sudden occurrence of "moonlight". Trish swings the machete at Jason overhanded, but in the next shot she knocks Jason's mask off underhanded. When Tommy first looks at the machete on the ground, the handle is resting on the corner of the rug, but when he goes to pick it up, it is not on the rug at all. After Jason falls to the floor, and has his head cut almost in half, the machete ends up lodged in his face. Right after that, Tommy picks the machete up, and it was just laying flat on the floor. The image of the hockey mask featured on the cover of the US video release is reversed and has the axe cut on the wrong side.