Really interesting concept! To answer the questions: I like how the game blends environmental aspects with a kind of fantasy setting. I would probably come for the world, but stay for the characters. And, I always prefer if there are choices in a visual novel. I don't think I'd have any problems with following the gameplay.
I am a huge fan of the menu GUI, really unique. The music reminds me of Japanese composers such as Kenji Kawai and Joe Hisaishi; the only thing that bugs me is the instruments are at times jarring, as if they were just put on top of the track and not written to blend with the texture.
I'd love to give a demo a try when it comes out!