The slasher movie subgenre has been dominated by a handful of reliable franchises and an army of parodies, deconstructions, and spoofs for decades. The golden era of the concept is long gone, but, there are a lot of classics that remain fondly remembered and franchises that still get new entries.
One of the reasons that slasher movies got so popular was their ubiquity. It costs very little money to take a handful of teens out to the middle of nowhere, dress a man in a mask, and fake a series of gruesome murders. With so many to choose from, a few were guaranteed to catch on, but what elements allowed the standouts to claim their thrones?
Who are the slashers who have managed to stand the test of time? Michael Myers from the Halloween franchise, Chucky from Child's Play, Leatherface from Texas Chainsaw, and Ghostface from Scream are still alive and well through multiple reboots. Freddy Krueger from A Nightmare on Elm Street and Jason Voorhees from Friday the 13th don't appear in films anymore, but they remain cultural icons. Other horror icons are still around but don't fit evenly into the slasher subgenre. Slashers are a special breed and for each one that has stuck around, dozens were less lucky. What are the essential elements of making a good slasher stick around?
Personality
Going back to the classics and watching the first Friday the 13th will reveal that some franchises didn't find themselves immediately. It took several films for Jason to find his iconography, from the mask to his favorite weapons. Circumstantial elements of the films, like the victims dying immediately after having sex, became core aspects of Jason's modus operandi. Jason never says a word, rarely has a moment of peace, and spends around 98% of his screen time committing gruesome murder, but he has a personality. Other killers find their direction within the first few minutes and only add on details as the franchise goes on. The key here is that the killer must be a character, with their own rules, motivations, and typical behavior.
Freddy is the high-watermark for personality. Robert Englund made the character who he was, and the one example without him in the starring role proved how essential his performance is. Chucky is also a killer who overflows with snarky humor and solid one-liners. Even admittedly lesser franchise Leprechaun stars a killer who loves to tell jokes. Though chatty killers have the most identifiable personalities, silent murderers still have their rules. Michael is a force of nature who kills as a matter of course and Leatherface might not speak, but he does emote. Imbuing the killer with an identifiable personality is key to making them stick around.
Rules
At their core, the structure of horror movies is often about establishing, following, breaking, and suffering the penalty for specific rules. Jigsaw will place the victim in a trap, but if they dismember themselves, they get to walk away. Freddy can kill anyone in their dreams, but if the victim drags him into reality, he becomes vulnerable. Providing a specific set of circumstances that convey to the audience when the killer is winning and what the heroes have to do to stop him are key to franchise building.
The hugely problematic Jeepers Creepers franchise recently attempted a long-awaited reboot. The original trilogy has some cult appeal, but the title character is a C-list slasher at best. Jeepers Creepers demonstrates the importance of this element by being a movie with too much iconography and not enough rules. The Creeper has a trademark vehicle, look, and several recognizable weapons. He picks targets and kills for a specific reason, he uses specific methods, and his powers are unique. But, for all the nonsense about the weirdly specific time he's able to occupy, the targets he picks, and the methods he uses, none of it affects the narrative. A good slasher needs strengths and weaknesses, to give sequels something worthwhile to play with.
Symbolism
Slasher movies are a uniquely suburban subgenre of horror. When the films don't literally take place in the sleepy cul-de-sac, the victims tend to come from that area and lifestyle. The horror of old mythological monsters tended to take place in the woods, the sea, or the sky. Places that were unexplored by the average person. As American life moved into boring identical housing developments, horror creators saw fit to imagine horror where others saw safety. That's why the most consistently successful killer is a faceless man with a kitchen knife, wordlessly eliminating one normal middle-class person after another.
The horror of deep space aliens or nightmarish demons is varied and interesting, but slasher movies are at their best when they bring terror to the most mundane imaginable version of life. The strength of a slasher is in its variability. When life changes for the average person, the slasher can change their tactics and the slasher film can change its setting. These films must always adapt to be scary, and if they can't, they'll be left behind.