The two central performances in this film - Oksana Akinshina as Lilya and Artyom Bogucharskiy as little Volodja - are quite magnificent. These are harrowing, difficult roles and the (then) inexperienced actors are remarkably natural. Their friendship is one of the most deeply moving in recent cinema and the devastating power of this film is, in large part, testament to their work. I love the tender moments in the relationship between the two characters - Volodja's reaction when Lilya presents him with a birthday gift is beautiful to behold. Superb acting, really.