Aside from the key moment just prior to the first choice you make in the story, Saya no Uta is masterful. Every route actually worked for me surprisingly enough, the OST lent itself fantastically toward the atmosphere, the sex scenes were perfectly uncomfortable and felt at home in the narrative, and Saya is honestly adorable. I'm a known lover of gap moe, especially moe horror, and this occupies that tiny space that my weird ass actually finds most enjoyable.