I rather like what I've played of this so far. It's nice that it lets me just be, if you'll pardon my bluntness, an abusive shitbag towards my student who works her like a slave by day and rapes her every night. I would not be surprised if this leads into some kind of bad end, but I know what kind of ride I signed up for.
I'm hoping to see a bit of expansion on your ability to be a shitbag. If Euna can sell you drugs to reduce lust and nymphomania, she should also be able to sell one that increase them. Especially if you can then use them on Kyoko and Niwair to corrupt them. Arguably, you should be able to use them on Euna and Suzumi as well, but I don't think it's necessary because Euna already seems like she's down for this kind of thing (she's willing to sell you a potion of mind breaking and is okay with lying to Suzumi to drug her with the futa potion, she is absolutely not a good person), and you can just rape Suzume as much as you want.
When Ast tells you what she has planned for Suzume, it'd be nice to say "but that's what I was going to do" or something, or perhaps when Suzume tells you what was happening to her, rather than "thanks for telling me" or "what a waste of time," you could say "that sounds hot." But as much as a "join Ast" route sounds fun, I suspect that that's asking a bit much, and is a long-term plan at best.
I like that the futanari semen is apparently an addictive and potent aphrodesiac (although the sex scenes do tend to refer to "rubbery cock" afterwards; I suspect that this is a bug), but the fact that it's sterile is less ideal. Hopefully there is a way to alter that later. Why stop at corrupting and breaking my student when I can breed her too?