Visual novel is quite a distinct category of games, which I don't make very often so like I said, it's mostly purely my opinion as a player. So it may just come down to personal preferences and artistic choices.
For the message screen, it's fine if you want to make it go up and down, but without any transitions in between it feels very jarring. If you put some quick fade in and fade out then it should feel much better.
To expand on the feedback on the writing, how I think about it is this: a video game's most defining feature its interactivity. Since most visual novels are played in a first POV, it can be thought of as a sort of role-playing game. I'm role playing as the main character, seeing the world through her eyes. As the MC, I don't want to be told how to feel too much, I want those feelings to come to me as player from the game. If the book shop girl is creepy, I don't want the MC inner monologue to tell me that she thinks that girl is creepy. I want to feel that creepiness myself, through her actions, her words, her visuals etc.
Again, I haven't played much visual novels in recent years, and it may be the case that the current taste is different to my opinion. Which is fine and maybe I'm just not the target audience.