So... is this a character creation VN or is there actually a story to this?
Again, literally one post above there's the answer. This game doesn't have a story, at all - like most of the Illusion games. They're just rape, rape and again rape with nothing really relevant.
In this one you just create your own waifu and then bang here all the way, unlocking something here and there (like... if I remember correctly, pills that make her go to the bathroom more often and then you can "surprise her" while urinating - and maybe.. having sex afterwards? Or just let her suck you off..? Don't remember very well, unfortunately - pills that make her sleep deeply and then you can fuck her while she doesn't wake up at all, and so on. Then there are for example even some "status" like "mind broken" and such that you can unlock only if you let it happen in the game, otherwise it's.. locked, sort of, always if I remember correctly). Simple as that.
But if you already played the original HS, then you should know and long story short (or TL;DR), no, it's the same game as the original. Nothing has changed.