I majored in creative writing in college and am hard at work on my own YA fantasy novel (and have been for a long time!). Your game moved me in a way I hadn't been moved since Doki Doki Literature Club, and before that by Undertale. I am impressed at how the symbology is neither subtle nor ham-handed: it is there to be seen if people want to see it. It takes a certain kind of confidence to say, "Yes, I will have my character hide in the literal closet," and then let the more subtle aspects come from what leaving the closet looks like (the player must not be seen leaving, but they *must* leave).
I was impressed by how masterfully this game uses the nature of the medium to its advantage. The diaries are obviously by different people, but everybody "knows" that anything established in the first five minutes of a game is canon, and the first five minutes of the game implies that the two diaries are the same. This aspect is particularly what I've been thinking lots about: what level of thought went into the introduction of the two diaries to make them *imply* being the same, without ever actually saying so? What configurations did you try before saying, "Okay, yes, this sets up the expectation I want."