The genre of “hot undead guy meets live girl” hasn’t played itself out on film. So I gambled that writer-director Jonathan Levine, whose morbid humor enlivened “The Wackness” and “50/50,” would freshen it up in “Warm Bodies.” He didn’t disappoint me.

He doesn’t have control of his story at all times, because the walking corpses behave inconsistently. Sometimes they sprint and sometimes they stagger. Sometimes they smell live humans (whose brains they must eat), and sometimes a person can fool them by mumbling and stumbling alongside the undead.

What Levine does have is a gently gruesome way of amusing us, converting the uneasiness of a wooer from another species into the everyday anxieties of a young man around a girl he likes.

He also has a knack for crafting a sweet, transformative love story, plus a respectful attitude toward Shakespeare. As soon as the zombie known only as R meets the normal girl called Julie, we know we’re in for a Montague-and-Corpse-ulet romance.

Levine adds one good idea to zombie mythology: When they eat a victim’s brains, they acquire his memories and feelings. So when R (Nicholas Hoult) munches on Perry, he takes on the late Perry’s attachment to Julie (Teresa Palmer). She’s the daughter of the armed forces commander in what may be Earth’s last human bastion, an unnamed city surrounded by a wall.

When R saves Julie from an attack and takes her back to the abandoned airplane where he lives, he experiences a human yearning for her and slowly begins to turn back into a man. Now he must teach his undead pals how to restore themselves, fight off ravening skeletons known as “bonies” and convince Julie’s dad not to shoot him down as a precautionary measure.

Fans of “Romeo and Juliet” will have a good time with the elements of homage – not just the balcony scene for R & J, but the behavior of R’s pal (Rob Corddry, playing Marcus instead of Mercutio) and the fact that Julie’s best friend is a gossipy nurse (Analeigh Tipton). R remains in danger of being killed by her kinsmen at any moment, and his “family” and hers consider each other mortal enemies.

Like most science fiction, you can appreciate this on a superficially exciting level or as a traditional love story, or you can read it as a metaphor: We’ll develop a healthy society only if we regard each other as equals and treat those who need extra help with patience and compassion. (Bonies can’t be reclaimed, so we must mow them down. I’m not sure that’s a metaphor for anything.)

Palmer, an Australian who convincingly nails her American accent, remains bland. Hoult, a Britisher who also sounds right, has a soulfulness that shines through, even while his communication consists mostly of grunts. (We hear articulate thoughts in voice-over.) I doubt that anyone who saw him 10 years ago as the title character in “About a Boy” suspected such bone structure lay beneath those chubby cheeks!