Since their rivalry is often quite funny, you don't have to squint too hard to imagine the same scenario played out as a synthetically broad and cartoonish mainstream comedy (I can just imagine it with, say, Ben Stiller and Angus T. Jones). The filmmaking team of Jay and Mark Duplass clearly love those comedies. Yet they work with a rhythm and tone, and a psychological fascination, that are altogether more realistic — closer, in spirit, to something the young Roman Polanski might have brought off. Cyrus may on some level be a stunt, yet the Duplasses' slightly sluggish, low-budget, mumblecore style allows this story to flower as both light-fingered lark and drama of suspenseful dysfunction.
Cyrus, who does nothing but hang out and compose spaced-out dance pop, has never outgrown his mom (nor she him), and Hill, with his deadpan parrot stare, makes the kid a brilliantly manipulative head case; he plays Molly's sympathies like a virtuoso. John, who knows that he's lucky to be with a woman this attractive, is in the vulnerable spot, but gradually he regains his power as a man, a journey that's less vengeful than touching. Cyrus cues us to expect it to go over the top, but the film never does. That may be its neatest trick.
