Cast the Expert: Robbi Morgan was a trained acrobat and thus well able to jump out of a moving jeep and run through the woods.
Contractual Purity: As noted below, Betsy Palmer was known as a squeaky clean goodie two shoes before this film. According to her, after it came out there was an outrage. Gene Siskel published her address in the paper and encouraged people to send her hate mail. He got the address wrong.
Cowboy BeBop at His Computer: When the film was aired on AMC's "DVD on TV" note Something they did in the early 2000's where they'd air a movie in letterbox format with trivia bits airing on the bottom of the screen it featured an interview with Robbi Morgan, who played Annie. After talking about her role in the film, she ended by saying she was honored to be Jason's first victim.note Which is wrong on two levels, because she wasn't even Pamela's first victim; that honor goes to the counselor in the opening
Creator Backlash: The only detail Victor Miller doesn't like about the film is the cop that shows up at the camp to warn the kids about Ralph. This scene wasn't in any of his drafts, and he wanted the camp to be isolated and away from any authority figures to give the impression that no one could save the kids.
Cross-Cast Role: A male stand-in was used for the first seventy minutes to disguise the killer's identity.
Enforced Method Acting: Ari Lehman, who played Jason was originally intended to only appear in a short flashback of him drowning. But the director decided to have him appear in the end as a surprise. He was instructed not to show anyone the mask he wore for the scene. The shock and fear on Alice's face is genuine.
Initially for Betsy Palmer, who was bemused and hesitant from the start and experienced a lot of backlash for the role. As the years went on, she embraced the movie and the sheer dedicated devotion from fans that had come to define her career.
Subverted for Kevin Bacon, who despite being the most successful of the cast has never been embarrassed to talk about it. This is the guy who spent the longest time unable to even mentionTremors.
Playing Against Type: Betsy Palmer mentioned how at the time she was typecast as a Girl Next Door and stuck doing game shows. So playing a "psycho-biddy" was quite a different role for her.
Reality Subtext: Mark Nelson, Jeannine Taylor and Kevin Bacon all knew each other beforehand, which is reflected in the banter between Ned, Marcie and Jack.
Reclusive Artist: Adrienne King opted to stop acting in films after a bad experience with a stalker and so only did voice over work for years. She didn't appear at a convention until 2009. But she has since embraced her fans and gives more interviews and public appearances.
Stunt Casting: Subverted. Harry Crosby's casting as Bill seems like it mirrors Jamie Lee Curtis's in Halloween (1978) (both being the children of Hollywood stars), but the producers didn't even realise Harry's father was Bing Crosby until later.
The bit with the snake in the cabin wasn't in the script but Tom Savini suggested it after his own personal experiences.
Robbi Morgan wasn't even auditioning when she was cast. She was in Julie Hughes's office when the latter looked at her and said "you're a camp counselor" - and she was on set as Annie the next day.
The bubbling effect when Jack is stabbed in the throat happened because the blood pump wasn't working - so a crew member had to blow it himself (they only had one take to use the latex neck).
Bill's eye twitching when his body is found is because the make-up effects were irritating the actor's eye.
The Friday the 13th Title Drop came about when the crew realised there was no reference to the date in the film.
Tuckerization: Steve Christie is named after the film's producer Steve Miner.
Urban Legend of Zelda: Rumors abound that Claudette's death was filmed and cut from the movie. The crew have said it didn't happen, but there is a still image of Claudette with a machete in her neck. This could have just been shot for promotional purposes.
Jason's original name was supposed to be Josh. Finding that to be "too nice", Victor Miller renamed him after a school bully he'd known.
The jump-scare ending wasn't there originally. Tom Savini had just seen Carrie (1976) and suggested having a similar ending.
An early draft of the script had Ned being a polio sufferer, with deformed legs and a muscular torso.
Marcie was supposed to be killed by getting an arrow shot into her chest while in the archery area. Contrary to popular belief, this was never filmed.
The original draft of the script had Mrs Voorhees losing her middle finger while trying to kill someone.
Adrienne King auditioned for all three female roles. Apparently her scream got her the part of Alice.
Estelle Parsons was cast as Mrs Voorhees initially. Producers also courted Penelope Milford for the role of Brenda, in the hopes of drawing more audiences in (as she had just been nominated for an Oscar). When she turned the role down, Estelle Parsons soon dropped out too - finding the film too violent.
Producers had plans for Alice to become a recurring protagonist who frequently had to fight Jason off - essentially making her this franchise's equivalent of Dr Loomis. Adrienne King's sudden retirement from acting - due to being stalked by an obsessive fan - led to Alice being killed off in the second film.