We've seen and read a million zombie stories before, but Warm Bodies does something different. It makes a zombie the narrator. Pretty much every other zombie story is told from the point of view of living people trying to survive (and clubbing zombies in the head while they're at it). The zombies are the Others, frightening and foreign. Julie explains it best when she says "We don't understand their thoughts so we assume they don't have any" (2.7.174). As a result, we humans do what we always do when we don't understand things: we shoot them.
But Warm Bodies shows us that some zombies, like R, our narrator, do have thoughts. And we're privy to them. As a result we kind of empathize with the guy. R is self-deprecating and as charming as a walking corpse can be. Even though he's killing people and eating their brains, we still kind of feel for the guy. How would the story be different if it were told from Julie's perspective? Or Perry's? Would you still have the same level of empathy with R? (Our answer? Probably not.)