I said earlier that this game is really really good. But constructive criticism is the best form of feedback in my opinion.
The one major complaint I have with the game so far is I don't like how the Toughness system currently works. It conflates assertiveness with immorality. You currently have two paths, either a pushover, weak willed individual who has moral qualms about the club (Nice Guy), or you play as a hyperconfident asshole who seems to revel in the debauchery (Asshole). There's a middle ground (Mischievous) but it seems ill-defined, plus trying to balance Toughness in the middle can make MC seem bipolar or schizophrenic - showing concern in one decision but then being brutal in the next.
I wish there were separate "Confidence/Assertiveness" and "Depravity/Immorality" stats. This would allow for two more personality types in addition to the above:
The "White Knight", assertive, "moral" protector. You're in the Club for the "right" reasons. You want the money for med school, and you justify being at the Club because better you than some immoral bastard with no limits. You're willing to work hard and do what the Club needs, but you have moral limits you won't cross, and you're willing to assert yourself against Kathleen and the others when it counts, even if it means sticking your neck out. You're a gentleman and a romantic (though not chaste) and you like being dominant, at least as much as possible in the circumstances.
The "Sly Pervert" - You haven't had much luck with the ladies, and now the Club has presented itself for all your depraved needs. You don't like being direct and have never had much confidence, and instead much prefer to manipulate and blackmail to get what you want. You're happy to be a willing lackey for the Club in its worse form (at least for now), though you care more about appearances than anything else. Would kind of work with the Social Chameleon.
The trait system is kind of meant to represent this but I feel it's too sporadic and isn't well integrated into Edwin's character. Though obviously an addition such as this, this far along is unrealistic and would add to the workload, though I hope it can be improved in some form.
Also just my two cents on Killian given it's the current topic: I find it hard to like Killian because he seemingly doesn't have any redeeming qualities, while at least you can play Edwin to have some. Well, the only redeeming quality Killian sort of has, is that he's loyal to Edwin (and his mother) and is willing to help him out. Otherwise, he's pretty unlikable and irredeemable, he shows no moral qualms about the Club and revels in it, cheating on Mina, is a spoiled rich kid etc. Not that's a bad thing for the story, he fits right in. But I have no real motivation to try and improve my friendship with him, other than some kind of misguided loyalty to him. Killian needs that something more. Maybe the "convince Killian to go to college" subplot will address this, I'm looking forward to seeing it develop.
Other that that, I have no real complaints about the game. Story is intriguing and well-paced (a big problem for many other VNs), decision are meaningful and aren't enigmatic, characters are well written and there's loads of room for exploration and character growth, renders are great (whether you like Honey Select is a matter of personal taste).