Sorry to say that personally I think this piece is the worst load of nonsensical rubbish which I've ever heard. I listened to it once and that was too much. Marc-Andre Hamelin's recording is fantastic but as a piece of music I just don't like it. I do like some of Rzewski's music, especially the North American song transcriptions (I'm working on "Down by the riverside" at the moment), but this 30 minutes of brutalising the piano, whistling, singing, shouting, etc. is not for me, I'm afraid.
Gregory