I like the graphics and lightning! I would love to see a somewhat eerie soundtrack added to the game, that would give it an incredible tense atmosphere!! Because the mice can be quite scary..
Viewing post in The library of the evil book jam comments
Have look at these, maybe there's something you would find fitting:
https://incompetech.filmmusic.io/topics/horror
They're mostly (maybe all) licensed under Creative Commons with Attribution. So you can use them for free if you credit the author.