I would love a procedurally generated horror game. Like, everything. From the monsters to the maps and such. It should take place in a future setting and the monster will be procedurally generated with random parts. Like Spore, or that one game where you just watch a creature evolve, Each part should give some sort of stat to the monster, like speed, damage, etc.
There shouldn't be any jump scares either, just ambience and a couple monster that will chase you, and creep around corners and such. You wont be able to fight back at the start, you'll have to hide a lot, but at some point you'll be able to get something like molotovs to scare away the monsters, and potentially killing it. That would give you some time to make progress until something new happens, such as you finding some sort of cloning factory that has been malfunctioned, producing a ton of these weird genetic monsters, so you wont be able to kill them all, but you'll be able to defend yourself.
The game should have some sort of detailed story too.