I've finished the game! Indeed, you really have to pay attention to the readme, and the same goes for the mini-game with sound (to understand that it's a grid you're navigating through).
It's a demanding game, but very enjoyable once you've trained yourself to distinguish the sounds. I did, however, occasionally deactivate the blind mode to progress in certain rooms.
A really great, rich experience! It would be really nice to have a "tutorial" room first, to familiarize the player with the sounds and the mini-game!