Plot hole: When Loco goes up the ladder in the barn, he looks around for Fox. But he doesn't see her hanging by her neck until he turns around to go back down the ladder. There's no possible way he didn't see her the first time he went through there - there's nothing blocking the view.
Revealing mistake: Near the end of the movie, as they are about to walk out of the barn thinking everything is over and Jason has been hung on the hook from the loft, if you look between the cracks of the barn door, you can see Jason being lowered right before the doors open.
Continuity mistake: When the cops arrive at the store, they approach and the white cop comes in contact with someone to move them away. The camera then shows the van driving, with the passengers all looking down at the store. The next scene then shows the 2 cops approaching the store again.
Continuity mistake: The size of the knife that Jason kills Debbie with changes size. It's so long that it goes in through her back and comes out her chest. Then Chris removes it from her neck and it's shorter. Then Jason throws it at Chris and it's even shorter than before.
Continuity mistake: When the "stoned" couple makes popcorn, it is shown being poured from a pot on the stove into a bowl, cooked properly. A short time later when Chris and her boyfriend are searching the house they come upon the pot of popcorn on the stove burning, and they empty it again.
Continuity mistake: Jason's left eye is much lower on his face than his right eye, but it sits in a normal position behind the hockey mask.
Continuity mistake: Vera drops Shelly's wallet in the lake. She stands up and tries to reach it. Seconds later it has floated a ways from the dock but remains in the same spot until Vera goes in the water and picks it up.
Continuity mistake: When Vera is picked up by Chris, she brings no luggage with her yet throughout the movie she changes clothes and shoes.
Revealing mistake: Toward the end of the movie, Chris runs outside to find Rick after she finds a bloody dressing gown in the tub. When she goes by the tree, Loco falls down from the branches. When he falls you can see his closed mouth open a bit as if he was smiling, even though he is dead.
Continuity mistake: During the one brief scene where we see Jason unmasked at the end of Part 2 when he crashes through the window and grabs Ginny, we see Jason has at least a partial head of hair. In this film, however, he's completely bald.
Continuity mistake: Part 3 picks up just minutes after Part 2. It shows Jason removing the machete from his shoulder. His flannel shirt sleeves are unbuttoned, whereas they were buttoned up in Part 2.
Continuity mistake: The last thing Andy sees is he walks down the hall on his hands is Jason slicing straight downwards at him with his machete. But this would have bisected him lengthwise, not at the waist. When we see his body up in the rafters, he's been sliced into a top half and a bottom half.
Visible crew/equipment: When Loco is watching the girls swing from a rope in The Barn Loft, he bends down to full with the gas can and when he looks back up she's gone. If you look closely by The Barn Loft door to bottom right there is someone moving with a blue jean leg. Jason is in dark khakis. So this is obviously crew.
Revealing mistake: When Jason is squeezing Rick's head, just before the eyeball 'pops' out for the 3D effect, it's obviously a dummy's head, as the face is wider and slightly larger than that of the actor's.
Revealing mistake: Inside the barn, the webbing that the deer head is covered in is fake, as it 'pulls' like elastic when Shelly moves his along the skull. Real webbing would adhere to his bare skin.
Visible crew/equipment: As Chris rushes across the cabin to slam the open window shut, crew members and monitor equipment are moving around in the reflection of the front windows.
Other mistake: After Jason slashes Andy in the hallway we see the machete ripping down through Andy's abdomen as he is upside down in his handstand. Then his body falls to the floor and Jason starts dragging him, but there is no blood spatter anywhere on Andy's chest, face, or the floor.
Continuity mistake: When Loco goes to the barn, he has a cigarette in his mouth. When he goes into the barn, it has gotten shorter although it's not lit.
Other mistake: When Chris finds Shelly "pretending" to be dead, if you look as she opens the door, you will see the door lock on the knob is outside the door, not inside.
Continuity mistake: Jason has dark Khakis throughout the film, until the very end. When the cops are at the house, his body is in the barn wearing blue jeans. In part 4 he is still in blue jeans, but then changes into dark Khakis after leaving the hospital.
Answer: Friday the 13th Part III in 3D is also available on Blu-ray as part of a set of all the films from 1980 to the reboot. I know because I own it. There are two pairs of 3D glasses included in the tin.
Alan Keddie