This game is one of this genre's pinnacle.
Seriously, the development with the heroines, the taboo aspect of it all, the risk of being caught and the seduction game played from both the main character and from the heroines too (specially Reika, she is sooo good) is what makes this game so great.
It all starts pretty tame but will quickly fall into debauchery of the highest order when you least expect it, some situations are incredibly hot and very well crafted.
It really is a fantasy powerplay if you are into this taboo, the progression feels natural, the dialog is carefully thought out, and each of the heroines goes through their specific process until they fall for the protagonist.
I can't recommend this enough, even if you are not into this kind of roleplay, the CG alone is well worth the asking price, and you will find something to like, as the heroines get more comfortable with their feelings the more shameless they get, and the more exciting it becomes.