Factual error: At the climax of the movie, Alice swings the machete at Mrs. Voorhees and decapitates her. When the blade makes contact with Mrs. Voorhees' neck, her head flies off at an incorrect angle, as though the cut began on the opposite side.
Factual error: After your head is cut off, you wouldn't be able to hold your hands in the air and make fists because your brain controls your ability to do this.
Suggested correction: Not really. There's such a thing as a death twitch. The a chicken's brain controls the ability to run, jump, and flap its wings, but it does just that after its head is cut off. A person could involuntarily clench their fists repeatedly when they've been decapitated.
You're comparing two different animals. The chicken with its head cut off that is still running around is still controlled by the brain. Part of a chicken's brain rests in the neck and when beheaded, it's possible not all of the brain is severed. This is not what happens to a beheaded human. There is a difference between a cadaveric spasm and clenching and unclenching your raised hands.
Factual error: When Jack and Marcy are sitting by the lake talking, a storm starts. At one point, lightning flashes "yellow" in their faces. Lightning does not flash yellow.
Factual error: There would be no slide latch on the inside of the pantry that Alice hides in before hitting Mrs. Voorhees with the frying pan. It would be on the outside.