First off I like to say that I'm a fan of the Zombie genre and RPGs, but not JRPGs or the doom & gloom European Zombie genre.
There's the obvious appeals:
Anarchy, chaos & breakdown of order.
Violence & shoot em up.
But then there's the genre's cliches:
Hand-waving modern military power.
Hand-waving the physics of decaying bodies.
Hand-waving the existence of militarized borders and quarantine.
Massive inflation of the undead.
The power-gaming stat fiddler in me is bugged by the hand-waving of reality, but it's not a big bother.
I can stand most the the cliches but the RPG enthusiast in me can't get around the last one; everybody dies. It's the same problem I had with the book series, if the supporting characters keep getting killed off and replaced then it's hard to get invested especially if the main character is just a sock puppet for the player. (yes yes not everyone dies in the book but I hated the frequency of character turnovers)
What characters do we have left? Kenny the broken, Ben the traitor, 3 strangers, and the child. There isn't much to go for except the child-guardian relationship. I don't like it, I don't expect it to change since it's a bad precedent to cave to fan pressure post-release, I guess I was just in for another type of RPG.