I saw this movie at the Stockholm International Filmfest. today and I really enjoyed it.
If I had to sum it up in a brief sentence i'd say it's as if the guy who wrote the "The Walking Dead" comic had written a Shaun of the Dead comic, and they made a movie out of that (I haven't read the manga this film is based on, but I assume that's more or less what it is).
It looks pretty expensive and has good effects and action, it's very well directed and acted, making the aesthetic of the film really paint its own manga-inspired universe.
The parts I didn't like is whenever it attempts to do somewhat serious drama, when it does it just seems entirely tone-deaf and alien. I'd give this movie a 3/5 and if they skipped the 20% of attempted drama and replace it with more over-the-top zombie comedy/action it'd be a 4/5.
I'd recommend this movie to most people and for zombie/nerd culture fans it's a must-see and likely a cult classic.