I saw The Sacrifice just now for the first time, and I have to recommend it for its graceful cinematography, thoughtful and serious minded subject, masterful use of colour and affecting acting performance from Erland Josephson in the role of Alexander. But I was fascinated and delighted by some of the other reviews here, especially those that acknowledge an oxymoronic experience: loving the film despite being bored by it.
Under 2.5hrs but slow-paced, Tarkovsky's The Sacrifice, like all his films, is visually beguiling for many viewers who are nevertheless wearied by the philosophising and meditative conversations. Yet I found it much more comprehensible than Mirror or Stalker. I wonder if Tarkovsky thought of a sequel to illustrate the consequences of Alexander's actions?
The real question is how one approaches the experience of sitting through a screening of a Tarkovsky film, as opposed to say, watching a Holywood summer blockbuster? For they are very different experiences, different works that make different demands of the spectator. I can't deny that I drifted part of the way through this film, but I sense that if I watch it again, and again, I will get more from it. It will become less wearisome, more stimulating.
I recommend this to anyone interested in Tarkovsky's work, along with Ivan's Childhood and also Solaris.