Perhaps its best to frame my feelings on the increasingly prevalent genre mashup film through a metaphor. Genre mashups, like restaurants, run the gamut. On one end of the spectrum is McDonald's. On the other end is high-end fusion cuisine.

Hollywood has become increasingly fond of the genre mashup over the years. At its worst, it's a clever little trick to appear original. Slap two seemingly disparate ideas together and you can create the illusion of freshness, even if it's really more like using a Glade plug-in to cover of the smell of a decaying dead boy. At its best, though, the genre mashup does have its merits. It can never be truly original -- after all, you're ultimately just creating some sort of Frankenstein monstrosity, no matter how successful you are at doing so -- but it can bring some fresh perspective to old characters, settings, even ideas.

It's a happy accident of the creative process that I've chosen the metaphor of a rotting corpse in a review of Warm Bodies because that's mostly where it falls on the genre mashup spectrum I have just laid out (and, well, duh, zombies!). Based off Isaac Marion's book of the same name, the film takes the framework of Western literature's most famous story -- William Shakespeare's Romeo and Juliet -- and lays it against the backdrop of these zombie apocalypses (apocalypsi? Apocalypto?) Western society has become fond of much more recently.

The Montagues in this story are zombies, though it is important not to confuse these Montagues with the skeletal zombies who have lost all trace of their humanity. I'm not sure which family they are supposed to represent in Padua. Anyway, R (Nicholas Hoult) is, you guessed it, Romeo, and he falls for Julie (Teresa Palmer) when he dines on the brains of her boyfriend Perry (Dave Franco). It seems in this post-apocalyptic wasteland, the undead are able to absorb the memories of the living and maintain some semblance of humanity, albeit not their own. Julie is the still-very-much-alive daughter of General Grigio (John Malkovich), who has taken on the rather gargantuan responsibility of protecting all of the remaining living from the undead in a walled and heavily fortified enclave. Ostensibly, these are our Capulets.

There's a little pluck and plenty of dark humor in a romance that blossoms because one of the star-crossed lovers quite literally swallows whole and digests his newfound feelings. It's fortunate, I suppose, that it was R who got to Perry's brains first and not, say, his closest zombie friend, the balding M (Rob Corddry) or a female zombie or someone much more grotesque than Hoult. But it isn't really enough to sustain a feature-length film. R grunting his love to a terrified Julie as he protects her from danger and ushers her back to the safety is a pretty good sight/sound gag at first, but it fizzles before long, and the predictable showdown between the mistrusting General Grigio and R's horde of well meaning zombies doesn't do much of anything to energize the film over the second and third acts.

Director and writer Jonathan Levine (50/50, The Wackness) brings an earnestness and tenderness that is quite charming to Warm Bodies -- qualities that are rapidly becoming a trademark of his. I'll give him credit for this as well: I totally missed the Romeo and Juliet thing until it was painfully obvious (R beneath Julie's balcony at night). I just wish that honest, unironic approach had been paired with something much less rote than zombie Shakespeare hybridization.