It's one of the only real rpg on this site and maybe the only real Hrpg ever.
Why ?
Because it's actually a Game, which is a requirement to be a rpG. It's a game in the sense that its basis was built around gameplay, not dialogs, not scenario, not even firstly around graphism, but around gameplay.
Because the gameplay, the core of this game, is created to showcase ero and porn elements. The fights, the side jobs and the Skill tree system revolve around the porn experience.
And because the gameplay was thought to bring replayability, which is not an absolute necessity for a rpg but extremely advised to have a rpg of quality (and quantity)
98% of the other so called "Hrpg" are just Visual novels in which you have to move your character yourself to see the next scene and spam spacebar to skip the edgy, immature and bad dialogs, with of course the most basic fight system in which you spam attack or something like that and get almost no sex element, if not at all. So there is no rpg element regarding combats, that's one thing, but there is not even rpg element for the "story" ! Why make a "game" for that when video or comics do that better ?
Anyway, Karryn prison should be considered the benchmark for hrpg .
There is a lot in Karryn Prison that could be better, even regarding the gameplay, but the concept of this game is the real deal.