Loved the notebook mechanic as all information you gather can be relevant with it. This forces you to stay sharp and inspect the information very closely. Really makes you feel like a detective. Also the mood and set design is awesome!
Apart from some minor bugs here and there, my main issue was that some of the puzzles can be "brute forced" still (for the padlock I simply listened to the sound on my first playthrough for example), because of which you can complete them without doing proper detective work. This can be confusing.
But you definitely are onto something! Best of luck and keep up the great work!