I just finished the game and it was quite an experience. I really like the creepy unsettling mood it gives off.
I have to say though, you might need to do something about that level with the keys and the one right afterwards. I get from the dialogue that they're supposed to be a bit demoralizing, but there are practical limits to player patience and to be honest I can see a majority of playthroughs just ending on a bad note at either of those levels.