I'm not usually into VNs. Some are alright but I like a bit of management (this game does have some very basic money management) and more freedom. GGGB, on the other hand, is a lot more than "alright". It's truly excellent.
Whatever GGGB lacks vs. the games I usually go for it makes up in terms of branching paths and choices that really matter. It's an impressive feat that characters' lives can go in radically different directions based on your decisions and each one of them feels natural. Some changes are rapid, others slower, but they don't feel forced.
The pacing of the story is spot on. Wherever you take the main character, the progress is gradual yet clear. Maybe it starts with a kiss in a club, it ends with you embroiled in a world of drugs and sex. Maybe you aim to be the good girl and the perfect daughter, and maybe someone really appreciates what a good daughter you can be.
In many games it's a frustration that your choices leave you "locked out" of other character progressions. In GGGB it demands a replay. This is because you won't simply be searching to unlock a new scene or two, rather you will see a new story, a new side to people you thought you knew.
Perhaps compared to a lot of games out there this one is somewhat vanilla in sexual content (maybe aside from the incest, which is trivially avoidable if it bothers you, and oh so embraceable if it doesn't), but for the sense of a character being truly corrupted I'm not sure I've played much else that touches it. Yes, their corruption might be more extreme, they might experience far wilder kinks, be subject to crazier circumstance, but here the corruption is so genuine that it more than rivals other stories of this nature. She really is a good girl, and she really does go bad.
From a writing and story perspective, and when considering the number of possibilities and replay value, it's hard to see how a VN could be better executed. There will be personal tastes about the story, there'll be those who don't fully buy into the art style, but this should set the bar for what games like this can be.