I think the game is great. I have always love VN and this one had all that make a good VN: the story is deep and well written (or well translated i would better say), the art too. The only reproach i will make is that i would love it to have some choice in it, like there is in most VN games i played, not a linear story like that. It would have been easy to make different paths regarding attitude of the MC toward Mizuki for example: the one present here, rape her in front her the kids directly to make her a sex slave or in the contrary being kind and become her nice boyfriend. The long time VN player i am was disappoint by that.
"the MC is an anti-hero in the truest sense "
We don't know how we would react if those kind of things happen. Rousseau was false: humans are not good in nature. And we live in a really individualistic society, even more here in Occident than in Japan. I think a lot of people (not me, but a lot) will just do that: try to save themselves, even if it mean let other people be eaten. I think the way the MC act is precisely what make this game realistic and catching in my opinion.
But this game also remember me why i almost NEVER play horror games (even more the non porn one). Those zombies (probably human create anyway) as just as barbaric as real humans are, the fleash eating in addition. Mostly i play those kind of games to evade the rotten real world we live in, not to reatrieve it just the same in those... I'm so sad and shaken after i play those kind of games and like the protagonist, i hate humanity even more. Most of the time i don't know if i will cum or vomit, i found that in some way exciting but also really uncomfortable. Will probably play vol 2 nevertheless.