Pleasant characters.
The author clearly knows how visual novels work and uses these elements well so that connoisseurs can appreciate the thoughtfulness of certain moments, plot points, and design decisions, etc.
Nice humor and a lighthearted (mostly) presentation of the story.
Good depiction of a specific style of architecture, character wardrobes, and their behavior.
The last couple of episodes seemed weaker than the others, but overall it didn't affect the general impression – I would play such a VN. Adding some erotic elements here and there would make it even better.