A word of warning: I watched Night Watch in the original Russian DVD release, not the American one by Fox(?), and I said "Boy, that movie had a neat premise, but really dragged toward the end, got confusing, and never lived up to its potential." Then I later watched the version the director specifically added special subtitles to, that was recut for Western audiences, and I said, "Now that was a movie."
So, be careful: they don't bother to make it as clear or well-paced with the first version as they do for the American release. You may (or may not) want to wait.