The song of…

I finished this beautiful VN today, and I have to say, 10 out of 10. Thank god for English patches.

The premise is quite simple, yet kind of confusing, our hero has a brain accident and a surgery which make his brain damaged and he sees other people and all of his surroundings as monsters and piles of blood and intestines. And in the middle of this awful world, in hospital, he meets normal girl, Saya.