In his films, Andrei Tarkovsky rarely gives the audience any help in grasping what is happening on the screen. He demands a level of attention and receptivity which is not always automatic with most audiences, since our viewing habits are formed by easier stuff. It's a bit like trying to read Heidegger or Kant after a life of reading nothing but pulp novels. In my estimation "Mirror" is his most difficult film. A depiction of the inner world of a dying man, the film jumps between different eras of the protagonist's life, with sometimes only very subtle connections between them. Shots are often composed for their emotional impact, rather than their narrative effect, the idea being that the audience will feel what the protagonist feels as he reflects on his life.
I often see films described as poetry, but here is a case where that comparison is most precise. Like poetry, layers of meaning are waiting to be discovered in this film. Each time I watch this film it affects me more and more. My last viewing, perhaps my tenth, was the most profound. I encourage everyone to give this film the time it demands, and deserves, because the rewards are great.
The quality of this dvd, like others have written, is not the best. The version put out by Artificial Eye in the U.K. is reported to be superior, and is probably the better choice if you have a multi-region player. I have given this disc 5/5 stars because the film is so great it overpowers the limitations of the disc, and there isn't a compellingly better version available in Region 1 at the moment.