Potent performances match director’s unrelenting intensity

21 Grams: Oscar nominees Sean Penn, Naomi Watts and Benicio del Toro have all been brilliant before, and if we’re lucky they’ll be brilliant again. But to watch these three – working alone and in tandem – is to experience the strange, immensely satisfying alchemy of great screen acting. Mind-bending and startlingly crafted, 21 Grams is absorbing drama that’s as much about loneliness, retribution and redemption as it is about the (literal) heart.