This is very much only a soft suggestion, but I could see this game going from a 9/10 to a 10/10 with some dialogue punch ups. The plot, characters, and story structure are already golden, I can't see much room for improvement there. The copy is clean, obviously the editors/proofreaders did a great job. But...some of the dialogue just feels a bit off, like it has been translated, proficiently, but it is apparent that it isn't a native/fully fluent speaker. Just the phrasing, idioms, etc.
Hopefully this is coming off the way I intended, and is not un-constructive criticism. This is a really impressive game, the bones and foundation are solid, the only thing I can think of to bring it even higher is making the English closer to native NA/UK speakers (no hard preference, though I enjoy UK English a smidge more).
[I've been up for awhile, and had, maybe, more than a few, so I do hope my comments aren't taken as an attack. Just ideas to sparkle up the facade even more.]