This is possibly the best zombie manga ive read, considering i usually hate zombie series. It does start a bit like a generic zombie manga but it becomes its own thing slowly. My best comparison would be this is like a mix of Highschool of the Dead and Summertime Render but with a more interesting plot and less fanservice (than HOTD)
Quick story summary ( Around first 50 chapters ): A zombie outbreak starts in Sendai from an unknown cause and the government seals off the area, leaving the main cast and many people inside to survive. As they fight they slowly find out more info about the zombies, and turns out they arent exactly zombies, but humans with too much evolution data that it has deformed them. After this discovery everything goes down to hell. The 'Zombies' start evolving even more and from now cast has to figure out where they came from and how to stop them.
Unfortunately this barely has a fanbase and the official english version was cancelled due to poor sales with only a fan translation thats on Chapter 122/267 as of this review, so its a bit difficult for western audience to get the full experience of this manga.
If you know Japanese or even dont mind manually translating the pages I really suggest giving this manga a chance. It is definitely worthy of getting a good Anime adaptation but its gonna need a bigger fanbase for that. From the other reviews it looks like people just dont give this series a chance and conclude their opinion from the first few arcs which is fair. The only reason i rated this a 9 instead of 10 is because it has a pretty mid start.
Overall,
Story: 9 - Very good for a zombie series. Has its starting issues and odd writing but very enjoyable
Art: 10 - The art is just really good. It keeps improving as the author continued this and its pleasant to look at. Has a bit too much ecchi for me but its less than many other ecchi series so not big issue
Character: 9 - Rare case of me actually caring about a fictional character. This manga does have overpowered unrealistic characters but the actual characters personalities stay realistic for a world end scenario. Lots of emotions, good character development and personalities. Only complaint is that a horrible character was kept alive for no reason other than to cause trouble.
Enjoyment: 10 - Very surprising to myself for enjoying a "zombie" series this much. I was so invested in it i read all 267 chapters in a single day
Overall: 9 - Definitely a must read for anyone into zombie / gory series. It has its flaws and slow start but give it a chance. Get this seri the fanbase it deserves because its way too underrated right now. I really hope we get a good quality adaptation of this someday.