Continuity mistake: After Brenda hears a noise, she puts her book down next to the candle, and walks to the door. When she gets to the door, the book is now by the opposite side of the candle. (00:52:50)
Continuity mistake: After Brenda is thrown through the window, she is facing to her right. Later when Alice goes back to the kitchen, she is facing to her left. The glass and wood around her changes too. (01:11:20 - 01:20:15)
Continuity mistake: When the kids are at the beach, Brenda shows up saying "Hey you guys. Ready to get back to work?", while placing her foot on a red towel. When it cuts the towel has changed position. (00:23:00)
Continuity mistake: When Annie talks to the dog, its position changes between shots. (00:07:00)
Continuity mistake: In the scene when Alice decapitates Mrs. Voorhees and Mrs. Voorhees raises her hands and grabs air, if you look carefully, the hands have hair on the back, even when, during the chase scenes, she doesn't have hair on the back of her hands. (01:27:55)
Continuity mistake: After Alice bangs at the lock with the end of the gun, the position of the lock and it's chains differs through the following consecutive shots. (01:17:50)
Continuity mistake: At the lake when they pull the floating object by the pier the girl on the right side is about ten feet ahead of the object. When it cuts she is behind it. (00:21:35)
Continuity mistake: When Alice runs into the barn to hide from Pam, as she slides the door open, a plank of wood falls over, to the right of the door. In another shot of the barn, it is upright again. (01:17:00)
Continuity mistake: When Enos is about to give Annie a lift he says "Ok kid, let's move", we see the red clothing going over her shoulder covering her bag's strap. When it cuts the strap is visible. (00:08:10)
Continuity mistake: Alice knocks the machete out of Mrs. Voorhees' hand, and we see it land. But when Alice runs and picks it up, it is in an entirely different place. (01:23:40)
Continuity mistake: As Annie backs into the tree, and then has her neck slit, her hair changes styles between shots, and the amount of leaves in her hair changes as well. (00:21:15)
Continuity mistake: When Ned is aiming the bow at the girl the angle of the bow changes between the shots. (00:18:00)
Continuity mistake: While Annie is talking to the woman in the bar the guy that washes the floors (that appeared earlier standing on the other side of the counter) now stands behind the counter by the woman. When Annie is leaving the guy stands on his original position. (00:07:55)
Continuity mistake: When Annie is hitchhiking and the red truck pulls over she is standing in the shade. When it cuts she is standing in the sun. (00:18:30)
Continuity mistake: When Steve is talking to Alice, and begging her to stay another week, he puts his hand up onto the roof as he talks. In the next shot his arm is down. (00:15:30)
Continuity mistake: After Alice hits Mrs. Voorhees with a frying pan, Mrs. Voorhees's arm goes from being by her head, to laying across her stomach. (01:22:30)
Continuity mistake: Just one shot before Mrs. Voorhees's decapitation, you can for a split second tell Alice's hands are empty as she swings, and that she's not really holding the machete. (01:24:35)
Continuity mistake: Brenda is seen swimming really far out to rescue Ned, and Marcie rows her boat out to the middle of the lake, yet when they rescue Ned, they are right beside the white decking. (00:23:15)
Continuity mistake: In the shop Annie enters, the tissue dispenser and boxes move much further away from Enos between shots. (00:08:05)
Continuity mistake: When Claudette and the counsellers are singing in the beginning, the close-ups of Claudette show her legs crossed, but the far-away shots show her legs spread apart. (00:02:10)
Chosen answer: Just after the credits, there's a bank sign that says "Friday, 13 - 7:01 - 60 Degrees". Then the DJ says "It’s 7:01 on Friday the 13th of June." and goes on to say some more about it and lists some other bad luck superstitions. At two other points in the movie, two characters (Ralph and Tierney) say "it's Friday the 13th". So there are at least four references to the fact that the movie takes place on Friday the 13th.
Myridon