Fun But Stupid: Count the Ways
1) Super zombie with the potential to destroy the world is being transported (where? why? who knows/cares) by clueless poorly-trained soldiers, in a container that can be damaged in a car crash. Wha?
2) Spoof an elaborate plan to break into a zombie infested area to crack a safe, when all you really want is a vial of alpha zombie blood, which would be a gazillion times easier to execute.
3) Hire a safecracker to open the safe. Because I wrote the combination down on a napkin, and lost it when I went to Chili's and they put too much sauce on my awesome blossom. Wha?
4) Establish zombie animals as a Thing, thereby invalidating the entire worldbuilding effort. One zombified bird, and the planet is DONE. One zombified fish, and it's done to the bazillionth degree.
5) Muddy the timeline (this actually helps the movie tremendously, so I get it, narratively. For example:)
6) For some reason create a "quarantine zone" that's maintained by the most ridiculous cliched set of characters ever, with the most ridiculous logistics ever, for the most incomprehensible reasons Ever.
7) Vary the abilities of the alpha zombies depending on plot convenience
8) Vary the abilities of the human combatants depending on plot convenience
9) Vary the effects of a zombie bite depending on plot convenience
. . .I could keep going, but this is the point where you either turn you brain off and accept the movie as seasoning for your popcorn, or turn the movie off and go read some Jack Vance.
6/10. Fun but Stupid.