I liked the characters a lot, been a while since I read this but I still think about it from time to time. I listen to the soundtrack every time a new chapter of a manga I'm reading comes out, too, so that's a bonus.
The first two important things to me are present:
I liked the game and thought the mystery, while intentionally quite obvious, is developed well. ベル's interaction with all the villagers is fun. The dialogue really pops.
My only complaint was I wanted more! It has a nice ending but I wanted to see more interaction between ベル and オリーブ.