A fan VN of a fangame is a clever concept right away!
The rough sketch style looks nice on the characters, especially with the detail and colors used. The backgrounds fill the space quite well, too.
The music sounds nice, although some parts are completely silent. This can be good in sparse moments.
The writing has various typos and other errors that somewhat distract from the reading. The ending also felt slightly abrupt, given the buildup - not to mention the presence of Kosuzu, the one who had a relationship question to begin with. Otherwise, it's a very straightforward but very sincere story that explores a relationship between Mystia & Kyouko.
One of my favorite parts was between Mystia and Byakuren, talking out their misunderstandings and fears of each other.
Despite the rough edges, it was a good read all the same. Well done!