Writer and director Bradley Rust Gray's loose, rambling Jack & Diane grafts a little horror-movie gore onto a basic girl-meets-girl scaffold. Between squishy emotional outbursts are interstitial bits of animated squish (by Stephen and Timothy Quay), like peeks inside some dark-hearted and carnivorous Victorian doll. It's not a bad idea — the rushing-blood tumult of love at first sight illustrated with cutaways to throbbing innards (and appearances by a werewolflike creature ready to pulp and devour the characters). But in Gray's hands, the metaphor collapses, unable to pull the weight of a script that's a refrigerator-magnet potpourri of forehead-smacking naïveté, tearful declarations and mean-girl dismissals.
As Diane, a childlike Brit visiting New York City, Juno Temple wobbles through the punishments that Gray has set up for her: nosebleeds, vomiting spasms, blackouts. Riley Keough doesn't fare much better as Jack, the skateboard-riding young lesbian who falls under Diane's blank pixie spell and must make pronouncements such as, "I wish I could unzip myself and put you inside me." Well, Jack, you may get your wish.
The performances veer from music-video remoteness to posed cool to moments of organic clarity, but the acting isn't the problem. Temple and Keough are believable enough, mostly when Gray's script calls for their characters to argue and misbehave. (Neither Jack nor Diane is likable, and there are moments when you could be forgiven for wishing that they both could be sent to the Magdalene laundries.) It's the story that doesn't work, all that true fear and fantasy choking on dubious words and fake blood, until you want to shout at the screen, "Don't go there!" Just like a real horror movie after all.