Billing Displacement: Adrienne King gets a third billing, even though she has less than 10 minutes of screentime and most of that is just a flashback to the first film. The credits don't even begin until after she's killed by Jason.
Crosscast Role: Jason's legs in the beginning of the movie is that of a woman, marking it as the only time in the franchise Jason was played by the opposite gender.
During the development it was planned that the sequels following the original one would have their own stories, and wouldn't have continuity with each other.
In the originally planned ending, Mrs. Voorhees' head was supposed to open her eyes before the credits start to roll. Sharp-eyed viewers can even tell that it's an actress in makeup rather than a prop. The sequence was scrapped because the producers felt the effect would be too cheesy.