If the dev is looking, and someone is able to pass it on to them(I'm not going to pay $3 to give feedback, personally and I feel it's a bit to early for me to throw money at it. Depending on what path the dev does take I likely may later though.)
My feedback comes from a more netorase stand point. I'm quite fond of the nts route so far, but I feel there are a couple of pretty big issues.
As Beast_Nevermore stated, and I'll echo
-Sayako should have more scenes of struggling with her new body. Like realizing she is horny for women and can't control herself -Lusting over Kana's ass on idk quest
-More resistance from Kana is needed Yuki I get, but Kana practically gives herself to Sayako after the breast fondles, and there is no sign of guilt from her fighting back.
-1 Sayako's current change is limited to her just masturbating herself raw for 3 days then deciding she wants to find someone to fuck. I'd personally like to see more of her struggle with coming to terms about her new body. The NTR path does offer a little more of a window into this, but it still feels lacking. It also sets up the Sayako entity to be pretty obviously some kind of avatar of corruption which isn't the case for the NTS path at all. How big of a divergence this causes in both stories is jarring and if you mean to have the same plot progression for the most part it really needs to be addressed ASAP while it's still early.
Suggestions: If the Sayako entity is meant to be some kind of avatar of corruption, and is just toned down in the NTS path I'd suggest having both Ayako and Sanako struggle with Sayako but be more resistant to the corruption and continue on the current NTS path.
-2 Kana indeed does need to put up some form of resistance. I get that again, Sayako seems to have some yet undefined powers of corruption, but the fall is immensely too fast. She goes from literally confessing her love to MC to taking that futa dick in the span of a day in game. It seems incredibly forced that even though she asks MC if he's fine with Kana helping get Sayako off, there's little to no hesitation beyond a failed hand job.
Personally, I'd also love to see the MC become much more involved in the NTS path. Sayako already seems to be quite a "bro" on the NTS path. She enjoys both sharing the experience, and being watched. I'd love to see her also include MC in some three-ways because of this. I know the Dev said there will never be futa on male, or male on futa (This personally makes me quite happy) but I do hope for some scenes where they're both fucking a female. This would also have multiple benefits.
1: It goes very far to assuage the issue with Yuki's immediate fall. If she was already sexually involved with the MC it'd be very logical that she'd be a lot more of a willing participant.
2:It puts her corruption ability further on display having the girls go that much further than they would before.
I'm of course not suggesting that the MC take the lime light, just be thrown more of a bone now and then. Hell, just let him take their mouth/tits while Sayako gets the good bits. I absolutely hope that suffering/humiliation/cuck-cage/sitting in a corner fapping while crying etc is
never, ever a part of the game, at the bare minimum a part of the NTS route.
I do like the game. As a fan of NTS and not NTR, the NTS path is quite great so far. I hope the dev addresses the above and I'm eager to see how the game gets fleshed out. I plan on likely supporting depending on progress. What effectively serves as the demo was spot on.