GGGB is, in my estimate, a rung above many other adult games. I'd recommend anyone interested in any of the themes to check it out.
- For one, it's the art style - while maybe not to everyone's liking, I personally dig it. Speaking of which, it gives the game a unique flair, and it's well done so far.
- Secondly, the choice system. Most games have this 1.5-dimensional choice between "angelically pure prude" and "total indiscriminate slut", which GGGB deviates from to an extent: You can actually sometimes gain "self-centered" points without taking a hit to "good person" points, which is nice. Also, sexual mores don't seem completely tied to this "me, myself and I" score; In fact (and please correct me if I'm wrong), it seems that in order to start some routes (namely boinking your dad), you need to have a moderately good "nice person" score, whereas to really get it going with your boyfriend's dad, you already need to be a self-serving bitch early on.
- Thirdly, while there's some linearity to the story, there's a surprising amount of stuff that only happens when you make certain choices, and not all choices follow along the altruist-narcissist distinction. Some choices even are only optional if you don't score too high on certain scores, I think.
- Fourthly, I love how there's rarely one-sided "good" or "bad" decisions: There definitely are decisions that aren't suited if you attempt a certain outcome, but I have yet to come across more than one decision where I went "why would I ever click this?" (see criticism below for the one offending option)
- The characters feel like someone actually thought about them instead of just inserting the usual porn tropes ("the hot MILF", "the massively hung ethical guy", "the Bimbo"). Even if some characters seem like those when you start out: So far it appears that they get actual character development, depending on your choices.
This all means there's a lot of actual replay value (certainly more than Mass Effect's "Do I go red or blue" variant provides). Depending on your choices, there may even be dialogue that just switches protagonists, which I found pretty hilarious. In fact, I'd say I had the most fun starting over and finding out how the game played out with different decisions ("Do I let get Jack into my pants, or would I rather he not?" doesn't just mean one sex act less for you). GGGB definitely is one of those games that start out as "well, that was surprisingly well executed and fun!", and gets better with each subsequent playthrough, because trying different approaches actually leads to different outcomes.
If there's one thing I think could be done better, it's some content for the "I stay at home to study" options - those feel like "skip content" buttons at the moment to me, and unless I missed something, they have no pay-off (yet). It would be nice if they could be spruced up a bit in that they help with certain routes (father comes to mind, or maybe Jessica with a "good girl" option to study together).
And a minor nitpick/confusion: Eric seems written to be unlikable. I mean, it kinda makes sense for those that don't want to fret with Ash cheating on him, or may even cheat on him on purpose just to get her away from this bore - but on the other hand, he's so soggy milquetoast that it actually demotivated me from an attempt to stay true to him: "Why would I do this? He's such an uninteresting wimp, staying with him seems pure masochism." Unless his route is just in so it doesn't get taken ;-).
On a "may be useful to people trying this out" level, since we're on Fenoxo's board: The game is purely about humans, in a non-fantasy urban environment. So no fantastic transformations, and there's very limited other modification (a handful of outfits and one tattoo, I think?) at the moment. I'd love to see some more possible changes (outfits, hairstyles, tats, piercings) in the future.
All in all, though, very well done. And even my criticism is more about "why doesn't this live up to the otherwise splendid experience" than about "the game isn't fun because of this".
I'm certain you will find it enjoyable and interesting! 
