Goofs

(at around 46 mins) When Terry undresses to go skinny-dipping, her hair is dry. In the very next shot, she is entering the water and her hair is moist and slicked back.

(at around 1h 3 mins) When Paul and Ginny leave the bar, there is a missing parking light on the front left of the car. When they get back to camp the light has been replaced.

(at around 58 mins) When Vickie is changing, the window in the mirror has no curtains. The scene changes to outside then back inside again, and the window now has orange curtains on each side.

When Amy Steel is hiding from Jason under the bed, a rat crawls up to her and creeps her out so bad, she urinates herself, they show urine coming out from under the bed. Moments later, her pants are completely dry.

(at around 41 mins) The cop shows no shortness of breath after running for almost a mile through the forest chasing after Jason.

Mark has a Microvision handheld by Milton Bradley. He refers to the two different games as 'football' and 'hockey,' neither of which were ever made for Microvision. You never see the games up close, but they are Connect Four and Blockbuster.

The film takes place five years after the first, which was released in 1980. But there was no Friday the 13th during the summer of 1985. However, Friday the 13th: The Final Chapter (1984) establishes that Mrs. Voorhees died in 1979, meaning the films take place on June 13, 1979 and 1984. June 13, 1979 was a Wednesday, as was June 13, 1984. June 13th was a Friday in 1980, but it wasn't again until 1986.

(at about 15 min) Jeff and Sandra are at a phone booth. If you look at Sandra while Jeff is speaking on the phone, she is actually watching their truck being connected to a tow truck. Then moments later (on cue, of course) she announces that their truck is being towed away, as if she didn't see the whole thing unfolding.

(at around 11 mins) During the prologue, the cat that jumps through the window scaring Alice was obviously thrown through the window by a crew member.

Ginny should have been soaked wet by running through the dense woods that leads to Jason's shack, since a heavy rain has just fallen. However, the trees are mostly dry. Also, moments earlier, the yellow car parked in open air at the camp is perfectly dry.

(at around 34 mins) When Terry is searching for Muffin, her tiny dog, she looks directly into the point-of-view camera that is supposed to be Jason's perspective, and significantly taller than her. She then calls out "Muffin?", as if expecting the dog to be higher than her eye level.

At about 50 minutes in, right after the skinny-dipping scene, Jason uses a machete to kill the counselor who is hung from a rope upside down, but we can plainly see that he uses the dull side of the blade.

(at around 51 mins) During the bar segment, the band is playing an instrumental number, although in one shot the front man can be seen singing "silent" lyrics into his microphone.

When the camera tracks into the bathroom for Alice's "gotcha" moment, the shadow of the camera is visible on the shower curtain right before she snatches it open.

(at around 19 mins) When Scott hits Terry in the rear with his slingshot, it hits her right buttock, but she grabs her left one.

Twice Paul mentions that women should stay clean during their menstrual cycles because they are in bear country. Women can rest easy as there's no evidence that bears are attracted to period blood and this is just an urban legend.

Vickie never tries to run when Jason slowly approaches her with a knife, instead just standing there.