Spoiler warning
This review may discuss plot details.
Mind, the first chapter IS questionable. Dubcon, *minimum*. I might even go further and say that the first volume doesn't really vibe with the rest of the series. They probably only planned to make one volume until the success drove them to write more. Also, those who come here seeking Last of Us will be disappointed. The story is much more romance than zombie apocalypse; and it's also a very lighthearted zombie apocalypse where not only is there little to no betrayal or group politics or whatnot. Also, later chapters show that you can actually reverse the process. This is also the kind of world where lovewill apparently stop you from zombifying.
All that being said, if you can set the first chapter and its dubcon aside (and I understand if you don't), there's a pretty decent BL waiting ahead.
The story weaves between the romance and the zombie apocalypse element pretty well. Characters are multilayered. The main romance is sweet, the smut hot. And the plot moves forward quite smoothly without introducing TOO MUCH drama.