The movie is not easy to watch, and it is long to sit through. Yet a certain joy shines through the difficulty. Tarkovsky has obviously cut loose from any thought of entertaining the audience and has determined, in his last testament, to say exactly what he wants, in exactly the style he wants.
He uses a great many long shots -- both long in duration, and with great distances between the camera and the subjects. Long shots inspire thoughtfulness from the audience. We are not so close that we are required to identify with a character. We stand back, and see everything, and have time to think about it. The movie doesn’t hurtle headlong toward its conclusion, taking our agreement for granted. There are spaces between events that are large enough for us to ask ourselves if we would do what the man in the movie is doing.
-- Roger Ebert