OK, I just played until the end of the current version, and rather then writing a review on a incomplete game (and one that I only played through once). I thought I would just share a few thoughts (and point out a few issues...maybe even put forth a question/suggestion or two).
Let's do issues first just so I don't forget to do them, and since you literally asked to hear about them.
1. Multiple times the color of the panties, and the description of them, don't match. Sometimes is says the are white when they are black, sometimes it is the other way around and/or they are describes as dark when they are not, ect.
2. In the scene where she takes her panties off, and holds them in her hand, she still appears to be wearing them (or part of them), but in the very next shot (same scene) she is not.
3. I got one Ren'Py error in one of the later weeks (once the second teacher is involved), but I don't recall exactly where (I followed the full corruption + hedonisms route if that narrows things down at all).
Ok, that is enough for "issues" let's move on.
As for sharing some thoughts I just wanted to point out a few things. I think the writing is solid, and the story is interesting enough, that I thought is was worth mentioning. The pacing feels just right, and the lack of any grind (or feeling of repeating task/events) is just so refreshing. While I think that overall the women are attractive they really are a bit to "sameish" IMO. I personally would love to see one of them with a reduction of breast size (I know this is just preference, but I had to try) for all the fans of more reasonable sized breast. As for the questions/suggestions let's just save that for another time. I didn't read the whole thread, and I don't want to ask stuff that has already been answered. Also, if we are being honest I have every intention of being back here at some point in the future.
Oh, I guess I should ask/mention a thing about the tags. Is is common practice to use the Lesbian tag for games with any girl on girl behavior (even if limited to a kiss...)? I don't really know the rules so this is more me asking then pointing out something is missing.
Anyway, good job so far, good luck with the future development of the game, and I look forward to seeing more.