Very cool game! I think it would be better if the monster periodically went into hiding, and then sprung up on you, as the scariest moment in the game is when you first encounter it, but the tension fades when you realise you just have to juke it. Could also be nice if the game paused when you pick up pages, because I can't get a good look before I need to dodge again.
Also I managed to get the secret ending when I checked the well, but I have no idea what the requirement is for it.
The art was very fitting and well made, and the sound of the monster are eerie. well done!