With the caveat that I'm somewhere around ch. 7, so things could get better or worse from here, I'm bewildered by how highly rated this game is. I'd put it somewhere between 2.5-3.5 stars.
Some of the renders are quite good. The older cousin is particularly attractive, and the aunt looks great as well, as long as you aren't too fussy about realistic body physics. Parts of the story are enjoyable; after the first couple chapters, the older cousin and MC develop a dynamic I really enjoy. Parts of the storyline with the aunt are good as a slow burn, but it's already gone on too long, and it has the feeling of something that's going to drag out to the point of being annoying.
That's where the good ends. The younger cousin is supposely 18, but behaviorally and visually is quite a bit younger, which, given her constant non-consentual interactions with MC is not ideal. And those interactions with her aren't avoidable, so hope you have a very specific set of interests, because you're going to get a lot of it whether you like it or not. The MC is a spineless loser, except when his aunt says no, and then he's made of steel. He also has all of the finesse of a rampaging gorilla; every time MC touches an ass or a tit, he grabs it like he's trying to avoid falling. There's a time and place for being rough, but it's the only mode MC has, and I feel bad for his aunt. The writing is passable, definitely not as bad as some of the mangled slop that gets passed off as English on this site, but there are enough mixed gender pronouns (he instead of she, her's instead of his, etc) and general clumbsiness that it's unlikely to have originally been written in English.
Overall, it's a middling game, with renders that are occasionally above average, writing that is okay at best, and characters that are largely terrible.