Look beyond the zombie imagery...
I'm a 29 year old guy who truly despises Twilight movies and everything alike. Warm Bodies was none of that. Twilight is a movie tailor made for idealistic teenage girls who know nothing about real life. Warm bodies is tailor made for intelligent and cynical people who have some knowledge of psychology and politics...
The key to understand this movie is to overlook it's zombie aspect. The zombie apocalypse is a metaphor for the dehumanization of our society. The Zombies are just normal apathetic people, who walk through their lives without ever being truly human. They are like the teenagers of today who can only send text messages to each or play on their I-phones, or like the bureaucrats who can't bother to greet you properly when you go and renew your driver license...
They can only «eat a brain» to feel, by stealing other people's thought. Which is a metaphor that means they try to be someone else, that they have no thoughts of their own. Hence, the zombies represent people who are not themselves, people who are slaves to the thoughts of other people, who cannot be «free».
In the beginning of the movie, R walks in the airport, goes through a metal detector with a TSA zombie who is still doing his job, not unlike an actual TSA worker... As R describes his «life»; walking around, not talking to anyone, looking at the ground,stuck in his own little bubble, he wonders how things were before the Zombie Apocalypse... And the next scene shows that things were EXACTLY THE SAME before...
Then comes the girl, who truly is alive. She is a true human being. She listens to no one but herself, she truly is free (from herself). The apathetic, emotionally dead young man, upon seeing her, begins to feel again. I could relate to that.
The reality of our time is that about 85% of the population is brain-dead and/or emotionally drained to the point where they are basically non-human. Modern society destroyed us. Most of those people were good kids, who could feel, who could love. Many of them just feel hopeless, they would love nothing more than to be human again. They feel isolated, all alone, when in fact, there are plenty of real-life-zombies who have some sort of inner life which they are afraid to show...
Others, are just plain scum, they have no more souls, they cannot be saved.
This movie was pure genius.