(minor spoilers ahead for people who haven't played yet)
Oh hey, a Twine game! Some of my favorites on itch are Twine games, shout out to House of Loki and Unbecoming.
Having said that, you'll forgive me comparing this to those. While I did get very similar vibes as them right from the off, the greatest parts of them and other text-based games you can perceive other than the text is the sound. The opening voice message is cool, I love it--- but the fact that it was the only audial element of the game kind of took away from what immersion you wanted us to have. If text is the only mechanical thing present, then having a good soundscape for interacting with the game or to up the immersion almost stops being a feature and starts being a necessity. So some accompanying sounds would have been nice, or! Have the voice messages be a constant for the first time you look at each postcard every playthrough. I acknowledge that this may muddy the line between left voice messages and postcards, which I think ties into the implications of Boni being able to (or wanting to) remember Maya's voice anyway, but other than that, it's good! All else taken into account, it's a game that turns out wonderfully personal depending on which words you click. Good job team!