I had this game sitting on my drive for almost week until today. I was pleasantly surprised by the quality (and an Isometric Yuri game no less!). The artwork looks great, it runs smoothly, the optional narrative is interesting, story pacing is good, and the characters are well designed (and sexy). Really strong start.
As a few suggestions, the camera angles are a bit too sensitive and fiddly atm. An optional feature to set side, top and down angles I feel might help for the puzzle segments. The sound design was really good, though I feel the Castle's music is a little ominous, could be a bit more cheerful/inviting, if you know what I mean.
I'm curious to know if the narrative options will lead to multiple endings or consequences to later missions? I think that will quite neat and dynamic.
Also, I have noticed your only on here and Itch.io as I write this. Are you considering other sites to expand your revenue?
I think you can get a lot of support for this game with more outreach.