"Hey let's make an ecchi series"
"But ecchi is so overrated and mainstream, I doubt we can make it any more interesting"
"How about we add some serious sh*ts in this series"
"Let's add psychological and suspense to make this thrilling, and add some horror elements too like plot twists in the first few chapters"
"Wait, isn't this a completely different series? Is it even an ecchi?
"No, the story is focused on ecchi elements"
"Are you saying you want to make some High School of the Dead kind of story?
"That sh*t is good, a true guilty pleasure series, but no, let's make the ecchi genre an essential plot device and not some meme kind of things like in the High School of the Dead"
"Can we make a story like that?"
"Yes, yes we can"
Basically, that's the gist of it, at least from the first 5 translated chapters. They made ecchi as the central focus of the story (Like literally, just read it), and there are psychological elements everywhere.
At first, you might not understand what's going on, but slowly you'll be able to. I'll give a 5 as of now since there aren't too many chapters that are being translated, but it has potential.
If you can read Japanese, I believe the series is already completed.