Hauntingly sad film about the vast emptiness of America. The long stretches of road, the open plains, the mountains in the distance that you can never quite reach and whose promise isn't quite real anyway. The "open road" as a trap, a lure so the emptiness can envelop and digest you.
Kit here is as much of a symbol as anything, allegorical like a horror movie monster, his James Dean looks and smooth talking charm hiding the same hungry emptiness that exists in the titular badlands. Holly is seduces by him as she's seduced by her journey into America, into the false ideal of pure self-reliance, into the acceptance of the violence that sustains her position as natural and inevitable. And why not? It's clear that Kit picked her because she was fifteen, because she was out alone without friends, because he could envelop her whole heart while still remaining at his core empty.