Cute! The lovely presentation with the charming sprites and a hint of friendly skeuomorphism adds a lot; it's one of those visual novels that announce themselves right in the title screen. Though I have somewhat mixed feelings about how voice acting works in this medium on the whole, I think it feels like an essential piece here as an extra layer of characterization that helps you get a sense of who everyone is with the story's short length.
Speaking of which, if there are criticisms to be made, I think there are some kind of curious choices with structure and pacing. The cast is large for something this short – the main arc you can identify involves the protagonist and Tibbs, but we spend a lot of time on getting to know everyone else (though the diary framing device expedites things somewhat) with little payoff. Even if the genre sort of excuses it, the dramatic incident that occurs close to the end is left feeling quite brief and weightless, too. I do wonder if a more focused approach would have helped give the final beat more of an impact.