I've finally gotten around to playing through this game and will agree that it's pretty good. Honestly would like to see a sequel some day even if I'm not sure how you'd handle it narratively. My main complaints are with the ending, the controls, and the short length.
I won't harp on the ending too much, since there seems to be a consensus there. The fact there wasn't a gotcha where Yuki turned out to be evil or victory actually being impossible is worthy of praise. Too much horror media thinks that a sudden twist at the end where victory is yanked away last second is quality writing. So I'm glad you didn't, even if I'd have liked there to be more choice in how it ends rather than be so vague. I'm hesitant to actually call it anticlimactic given that it comes after a difficult fight, but it'd work better with some falling action of some kind.
This might be a bit of bias, but I'm not too fond of the controls. Both styles feel clunky and the lack of controller support makes it harder to work with for me. That being said, this is a relatively minor problem in the grand scheme of things and I understand that a lot of work is involved with this kind of stuff. So I wouldn't worry too much about it in the long run.
As for the short length, I feel that it would've been nice to have a slightly longer and more involved story. As it is, it's not bad but I was surprised at just how quickly I got through it. I also understand that this isn't as simple as pressing a, "more content" button. And what's there is by no means bad, maybe a bit simple, but still good.