First of, let me say I'm going to be talking about Cabin in the Woods here. So, because this is a movie that it matters for: there will be SPOILERS for Cabin in the Woods.
After watching this movie, it sparked a very specific memory from back in college. No, I didn't go on a doomed camping trip. But I did try my hand at writing a by-the-numbers horror script, just to see if I could do it. The result was a script called Stacks of Evil. This was in '94. Watching Cabin in the Woods reminded me just how by-the-numbers Stacks of Evil was. It hit every single point that is part of the Cabin in the Woods sacrifice ritual. For the folks Downstairs in Cabin, the events of Stacks would have served perfectly.
Though it would have been a woefully mediocre movie.
But seriously: five college friends (A Good Girl, A Bad Girl, A Jock, A Brain and a Drunk, aka The Virgin, The Whore, The Athlete, The Scholar and The Fool) all decide they are going to sneak into the school's library to spend the night. Why? Because, that's why. They press on despite the warning of the janitor (The Harbinger). After some partying in the library, the Jock and Bad Girl split off, and the Drunk wanders off. The Drunk, specifically, commits the Transgression. He breaks into a locked room and knocks over a jar that houses a vengeful demon. The Demon then kills the Bad Girl, the Jock and the Drunk, in that order. The Brain and the Good Girl manage to figure out what's going on, and how to potentially stop it, until the Brain is killed, leaving the Good Girl alone to fight the good fight and survive to be the Final Girl. Because that's how it's done.
And I totally had it down that that is how it's done back in '94.
Because I knew my horror tropes.
Now, I'm not claiming that I wrote Cabin in the Woods first, because I didn't, because Stacks was nowhere near that clever. Though I did have a meta- ending*. But it does show how pervasive those tropes that Cabin plays with are. It hits the notes perfectly because they are so well known.**
After watching Cabin, I went into a TV Tropes hole for a bit, reminding myself about not only horror tropes, but sci-fi and fantasy ones. One thing I love about the Tropes page is the reminder that "Tropes are not Cliches"-- these are the broad brushstrokes of storytelling archetypes. Whether a writer makes them cliche is based on what they are doing with them. With Stacks, I was pretty much trying to be as cliche as possible. Cabin shows one can take those tropes and do something fresh and clever with them-- even with the fact that they ARE tropes in the first place.
*- Namely, after the Virgin "wins", there's a final "Jump Scare" where the demon comes back up, but then the film crew rebels and declares the whole thing ridiculous and goes home, leaving the demon decidedly unscary without special-effects backing him up. Kind of dumb, really.
**- My wife, not being a horror movie fan-- at least, American horror-- was not familiar with these tropes, so much of the meta- aspect of the movie was lost on her.