Love the art style; it's so gorgeous.
Just in case you didn't know, it appears that the game can't be installed on Mac when using the itch.io app - direct downloading works fine though.
I ran into this issue with one of my VN's - in the "Edit Game" screen, tag each of the builds as "for Mac" or "for PC" (there should be a checkbox) and then it'll load fine on the app.