While it seems like a generic slasher on the surface, The Slumber Party Massacre is notable for being one of the few entries in the genre written and directed by women. Writer Rita Mae Brown intended for the movie to be a feminist parody of the horror movies that were exploding in popularity at the time. The studio, however, wanted to turn it into just another one of the movies it was supposed to lampoon.
Director Amy Holden Jones seems to have deliver a movie somewhere in between, though one which is probably too much of the latter to be a true parody. There seems to be some pretty genuine portrayals of how young women can be both cruel and caring toward each other, and the movie does a fairly good job of distinguishing its large cast of female characters from one another, giving them different ambitions, temperaments and reactions to the killing. That being said, it also contains two scenes clearly intended to do nothing more than show as many naked women as they could (both of which made it prominently into the trailer).
The slasher himself matches the semi-humorous tone of the rest of the movie. He seems to be nothing more than a somewhat dumb and sexually frustrated everyman who murders the girls with a large electric drill. Contrary to what is most seen in these types of movies, he has no mystery to him, no iconic disguise and is far from unstoppable.
In the end, I liked the movie, but more often than not it blends in with its genre rather than saying anything about it.