I'm not gonna say the anime is bad, but there is no way it's ten out of ten. Got to be honest, I mean it took them 17 episodes to learn how to draw mouths from the side. That fact alone would make it alone a 9/10.
Bro I totally feel ya, this story hits a bit too close to home. Essentially this manga/anime, like many other, is critique of modern society, in this case neet subculture. I may be over analyzing this but when you think about it, put some pieces together it is obvious that:
This fantasy world is projection of his own mind, where he is controlling characters from the very start like every shut-in shizo worth his salt (takes one to know one). Didn't you notice conversation from the beginning? No matter who he meets, it is like he's talking with himself and not a total stranger in unknown world. Another trait all characters share is extreme hostility towards protagonist. That is because he hates himself. Strangers aren't interested in reading the person they encounter, no way anyone would react to him in such hostile manner. As story progresses, his mind changes. You see he's shizo bi-polar type which perfectly explains abrupt switches from love to hatred, from joy, romance and comedy to despair, horror and death. He's self flagellating himself through the whole story. I think he is that cultist leader, they share same little quirks. That spirit is also part of his mind. However, he finds some love for himself through the process, something he don't have full control over which terrifies him because every shizo/shut-it loves to be in full control of his non-doings.
Maybe I'm over thinking it, but it does seem the author is former shut-in, neet and bi-polar person. I can't see why someone who isn't, would be so critical, it is known that most critical of certain behavior are people who experienced it to the fullest. Fat shaming comes from former fatties, abuse of alcoholics is mainly thing former alcoholics enjoy, poor people are treated badly by those who escaped poverty etc.
Self flagellation in episode 18 can really be too uncomfortable for some, especially those who find themselves to be in same situation as protagonist. It is excessive and can force someone to stop watching. You need to take in consideration that this is Japan we're talking about. Crazy country built on extreme working habits who also got hit by most unusual predicament, NEETs. Their hatred for such behavior is through the roof, mainly because of their working oriented culture.
Edit: This is an excellent read on the matter
THE MELANCHOLY OF SUBCULTURE SOCIETY