Continuity mistake: When Ali punches the car windshield, it is clear that the whole pane of glass is smashed out, but in the next shot the pattern of the missing glass is completely different. (00:32:15)
Continuity mistake: When Shelly screeches out onto the road, after the windows on the car are smashes by Ali, you can see a large 'Olympia' lorry parked perfectly straight, outside a garage. Then between shots when Shelly goes speeding towards the gang's motorbikes, the lorry is suddenly parked at an angle, now sticking right out into the road. (00:32:20)
Continuity mistake: When Rick is about to go for a drive in his car, and Chris is begging to come, we see Rick is holding just keys and that Chris's hands are empty. It cuts to the POV of Jason watching them from the stable, and Rick hasn't moved or picked anything up. It then cuts back to a closer view of them again, and now Rick has a golden coloured coat in his hand. (00:33:50)
Visible crew/equipment: When they get into the car you can see two of the film crew members moving reflected in the car window. (00:34:25)
Visible crew/equipment: When Chris and Rick are getting into the yellow Volkswagen Bug the cameraman can be seen in the reflection of the car's window. (00:34:35)
Visible crew/equipment: When Loco, Fox and Ali stand by the van before they steal the gas, the long black boom pole is clearly reflected in the back window of the van. (00:35:25)
Visible crew/equipment: As Rick and Chris get in the Volkswagen Bug after Shelly returns it, you can see three crew members in the backseat window reflection. (00:35:55)
Plot hole: Jason is standing in plain sight of Chris and her friends and no one even notices? The sun is even shining on him. (00:35:55)
Continuity mistake: When Fox closes the door at the barn we can see she is closing the right door. When it cuts from the inside we can see her closing the left door. (00:36:25)
Continuity mistake: When Fox looks up the ladder, we see the edges around the ladder hole, and the floor is covered in hay. Moments later, when Loco looks for her, he climbs up the ladder, and there's no hay around the hole. (00:38:05)
Continuity mistake: Jason approaches Loco with a pitchfork with five prongs, but the pitchfork that enters Loco's stomach has only four prongs. (00:40:20)
Continuity mistake: When Jason moves to spear Loco with the pitchfork, the prongs are curved down. But when it goes through him, the prongs are suddenly pointing upward. (00:40:25)
Revealing mistake: After Loco has been killed, it cuts to a shot of Fox, who is pinned up on the rafters with a pitchfork. She is clearly moving, however, despite trying hard to stay still. (00:40:40)
Continuity mistake: When Ali is looking for Loco and Fox, Loco then rolls off the rafters onto Ali. In this shot you can see no blade leaning against the stable. Then when Jason jumps down, Ali grabs a blade that has appeared. (00:41:15)
Revealing mistake: When Jason is hitting Ali in the head with a club you see Ali move all three times he is being hit before the club is near him. (00:41:50)
Continuity mistake: When Chris and Rick get stuck in the woods, Rick puts a coat on Chris. In a wide shot Chris pulls the sleeves of the coat up and then starts adjusting the shoulders of the coat. It cuts to a closeup and she is now rolling the sleeve up again, and then adjusts the shoulders again too. (00:42:35)
Audio problem: When Andy says to Debbie "How do we do it in a hammock?" his mouth doesn't move to the word 'hammock.' (00:46:05)
Continuity mistake: When Vera is sitting by the dock, Shelly grabs her foot from underwater. In one shot, her shoe clearly comes off, then moments later is back on perfectly. (00:53:40)
Continuity mistake: When Vera says "I never said you were a nothing." to Shelley you can see Shelley holding the harpoon pointing up. When it cuts he has it lowered out of sight. (00:54:30)
Visible crew/equipment: When Jason is shooting at Vera with a harpoon you can see the wire attached to the arrow. (00:57:50)
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