This was such a fun visual novel! It really was well made; the story was really enthralling and pulls the reader/ player into the story and game through that. The constant reminder of the bitter and cold snow always there in the background as music, the unnerving feeling of a random person being in the cabin with the character and then the realisation slowly dawning in on the player that the story might be real after all.
It was all executed really well!!
The only thing I would suggest would be that in between the story, Erin would go 'ghost mode' and maybe look scary if you flip to a certain page or she might be looking over the book at the character or maybe have a smol smile or something. That would really encapsulate everything and add some more depth to the already great environment you've built!
One other thing would be the ending; it seemed super sudden and Erin just vanishes with the bloody text on the wall. The text didn't seem to match with the setting you built as the window and Erin herself looked more realistic compared to the bloody, and also Erin just disappearing didn't really seem to add to the build up of the story? Or that might just be me.
Though I do have to say how Erin disappears when the torchlight leaves her model was a really nice touch!
The above thoughts and suggestions are just my opinion but I do have to say that you have crafted a really enthralling and wonderful game and world inside of it in a really well thought out way! It really was indeed great to play and experience!
Good luck on future projects! This really was a great game!