The first 70-75% of the book is the survival guide part. I would be generous saying it's worth 1 star. Not to say that it wasn't well-done (note: not well-written) but it is lacking the straightforwardness of a real survival guide while simultaneously too conversational to be believable. I would give someone fair odds of survival following the instructions - in a fictional world. (If only I could send a copy to the characters of The Walking Dead in season 1, episode 1!) It could, theoretically, provide a sound basis for real life survival but I wouldn't believe it entirely since it is listed in the fictional section of the library.
Another thing that annoyed me is the narrator's tone comes off as soap-boxy. As a rant against all the improbabilities and stupid choices made in all zombie movies, ever, it's great. Satire and irony, 10/10. But as a prologue (?) or a stand-alone novel, it's just annoying.
Also, as I read this as an e-book, there are a ridiculous number of stupid little pictures included in the text, which just look bizarre. I would hope it looks better on a printed page. The tables/lists register as images on the Kindle, so I was constantly accidentally tapping them when I was trying to 'turn the page'. Probably not a problem for all e-readers, but another tick against this book for me.
My favorite part was the last 25% of the book which is the alternate history section which actually provides background for the world described in the book where zombies have always been a problem. So that aspect is different from other 'verses in the zombie genre. Rather than being the result of a disease or curse or whatnot, zombies (specifically differentiated from voodoo zombies) are a naturally occurring phenomena that no one knows the origin of but hints throughout the book indicate that it may have been something that happened once - long ago- and perpetuates due to never being fully eradicated. (Think ice zombies.)
In conclusion, the last 25% of the book salvaged my opinion of it and I am moving onto the World War Z book and audiobook (simultaneously).