Well, some of the posing and sex scene ideas are okay. Some narrative notions would have potential if dialogue wasn't unhinged. Model work could be a lot better, but I've seen a lot worse.
But all of you who consider writing in this excellent, what the fuck are you smoking? It's an incoherent mess. All 3 main characters have a combined IQ of 70 at best, most of it in Julia, who is also completely psychotic. What's worse, the writing was deteriorating more and more as the time goes on, and no, terrible translation had nothing to do with it. It's like talking to a person who is slowly losing their mind. This is beyond someone who is an antisocial permavirgin who has no idea how real people talk or behave.
I think the phrasing in dialogue is often awkward, which I chalk up to it being a translation.
I also think there wasn't really much going on in the story, but that's okay because it is a porn game. The narrative is meant to enhance the eroticism, not be a satisfying story. Far too many porn games try too hard to have a story that is good as a standalone story rather than a story that pushes and enhances the erotic element.
What this game does better than almost any, is portraying a brother/sister incest dynamic. Most other games either resort to some kind of gimmick as an excuse for it; whether that is mind control, magic, blackmail, or whatever else; or they just have everyone be a huge slut willing to commit incest for no good or explained reason.
The MC doesn't have that much personality (he's supposed to be a stand-in for the player and allow for different choices and player agency, so that is fine), but Julia is very well done. She isn't a psycho or bipolar as someone else in this thread complained, she is deeply conflicted because she is attracted to her brother and she knows she isn't supposed to be.
That is why she is sometimes teasing, other times pushing him away, other times trying to create some kind of flimsy justification for why she is continuing to tease her brother and do sexual things with him.
And through it all she doesn't act like she is infatuated or in love or anything (it is deeply unsatisfying when incest storylines are treated as some conventional romance), she continues to keep an older sibling/younger sibling dynamic going. It is why she feels jealous over her brother and also has trouble trying to define the type of relationship they have or want to have.
So the game has a satisfying porn narrative of the two main characters overcoming the barriers of incest in a fairly realistic manner. That is why I think it is such a shame it isn't likely to be continued.