I don't really have anything new to add about Rot & Ruin other than throwing in my voice to chime with the naysayers in a bored "Nay!" I may even be lip synching. I'm not feeling the effort at all.
Imagine the most stereotypical response of a fifteen year old boy and apply that to any points the zombie killing concept/teenaged boy living in a post apocalyptic world can dredge up and that's your book. Stir in a dash of "I should have cared all along!" and generic teen friendships story. Add a pinch of romance. Yawn. To continue with my lame-o cooking analogy, none of the ingredients had any flavor.
Sorry for the uninspired review. This book didn't inspire much of anything in me. I blame Rot & Ruin! Will this mediocrity never cease?