So you probably want to know what even is this. How much hentai is there? Well...
First, it's a short, joke game, so don't get your hopes high. It's a joke that combines some nice artwork with asylum-level writing and some horror-ness. The gameplay is not very good, if you know what Daggerfall or at least Wolfenstein is, you'll understand how it plays.
Is it good as horror? No, though i'll admit it's a bit tense at the beginning. No screamers, so i was relieved to see what happens when Onryo catches you.
Maybe it plays well? No, it doesn't, though it's very short so you won't get tired from it.
Is it good for fap, then? It's not either, scenes are basically just pictures, though endings do have scenes with writing. They aren't bad, but it'll not be enough.
Writing? The writing tries to not make sense, and it succeeds, it doesn't make sense, since it is not serious. People talk about jokes being cringy. I, personally, almost never find any joke in games to be "funny", it either annoys me, or makes atmosphere not serious. This time it didn't annoy me, and i didn't mind.
This game is an experience, just to spend some time having fun, doing something different from what you usually do. Play it ONLY if you're okay with it, or you will be frustrated.
But i'll give it a 4 anyway, because of the light puzzle and that one ending that crushed my hopes, i thought i finally found a cuckquean content, but no, it stopped halfway and switched to the regular ntr stuff...