The very end (SPOILERS)

I was totally blown away by the ending. I might rank it as one of the most powerful endings I've ever seen. The suspense... after 20 years (or however long it was) in prison wrongly accused, would he be a bitter & spiteful man? Would he be completely insane? We chase him down the street not knowing; we watch his vapid expression which gives no hint. We feel like we'll lose him and never know. Then he finally turns around, and at the very last second... he smiles. If that aint good cinema, I don't know what is.