Overall, alright. First of all Forgotted review is mistaken in not being related, in the end it is revealed that we actually are blood relatives. So if it's important for incest lovers, here you go.
Great porn, bad story, great models and good animations, super unfinished and ends abruptly so it's more like a prologue, lasts for couple hours at most.
In slightly more details, the story is completely typical but the issue with it is a complete lack of buildup and connection, sex happens WAY too quickly and things that should take some time and have actual arcs (like Gwen going from bitchy unaccepting sister to sweet and mellow one) happen in a blink of an eye, leaving very rushed aftertaste, and this is the case with everyone. Doesn't help the situation that it's literally what would be end of chapter 1 in any other story, the game ends unceremoniously the moment it is revealed we are blood related out of nowhere and jarringly boot you into main menu after black screen. So "completed" tag is a lie once again.
Models are geniunely great, animations are also better than average but i'm not a fan of having a list of repeatable options you can do until you are satisfied, sex scenes are part of the narrative and they also should tell a story, instead we can just pick repeated positions and it leaves you with honestly kinda pretty but soulless scenes.
It is perfectly fine, unlike most of the slop that comes out this actually got some quality behind it and for incest-harem lovers worth experiencing, just be aware that story is pretty bad and it ends abruptly when it barely get going.