Here's the thing: despite its marketing, it's not trying to emulate slashers. Hell, I'd argue outside of the basic atmosphere, it's not even inspired by slasher horror. If that were the case, we'd have a 'slasher' already: even without a victim and by that, I mean someone to keep the storylines connected and keep tension up. That was teased to be Alex but who knows at this point.
I'm not sure what marketing you are referring to. The front page has a blurb about a horrifying mystery, but in AVN world that's much more likely to refer to a cabal of horny witches or sexy demons than to Michael Myers. I definitely didn't start playing this game expecting a slasher-inspired setting, but it is very obvious to me that that's what it is in-game, so it does that well.
The atmosphere, the camping in the woods, the shitty teenagers/young adults, the previously disappeared young woman.
That's all before we literally see one or more people stalking the cast, or the sabotaging of their equipment, the bloody knife, etc...
It's true that we haven't seen someone killed yet, but that's not that weird since this is still an adult vn where the players would rather have their mc sleep with the girls than see them killed, so if there is any killing it will be towards the end.
I don't watch CW soap operas, but the fact that they share similar types of drama doesn't make this not be slasher inspired. Slasher are full of shitty teens who are constantly horny, they will obviously be drama filled. Games can have multiple inspirations
Mei is the weirdest part of all this, from final girl hommage to whatever is happening now. I agree that her storyline is the one that most breaks the slasher vibe