This work originally started as an online journal where each entry was uploaded piece by piece and appeared as if it was hand written by the protagonist as he tried to survive a zombie apocalypse. It was published in this unconventional way because J. L Bourne wanted it to feel real and raw and was quoted as saying "there are no publishers or editors in the apocalypse." Eventually this unique work was compiled and morphed into book form but the journal entry format remained in tact which is a good thing since it happens to keep the story moving forward rapidly. Couple that with the credibility that Bourne's 22 years of military and intelligence service brings to his main character, who is also military, and you have a unique work worth experiencing within a very crowded genre.
That being said this book isn't perfect and there is only so much that can be done in such a short novel. At times things feel rushed as the main character has emotional highs and lows that don't match the amount of time that has passed for the reader and there also isn't much world building that gets done. If you want background details into the root cause of the apocalypse that is going on then you will be left wanting as the writer of the journal has no clue what is really going on and all you ever learn is what he is able to sort out as things progress. So don't expect much in the way of resolution as this is an introduction to the series and it should be approached as such.
Since this is a short story it makes for good reading on a trip where you don't want something too deep or listening to on a long car ride with the audiobook clocking in at just over 6 and a half hours. As usual Jay Snyder does an excellent job narrating the audiobook and he is a good fit for the material and he keeps you engaged.