Yes, it's slow. So what?
It' s the biggest cliché on comments that this film is so slow. This film is not a pop-corn movie; you must think and feel while watching it.
Besides, it has a good storyline and storytelling is brilliant. Visuality is on top, and very well acted.
If you call yourself as a cinephile (cinema-lover), you can't get bored on this film while watching it; because it has too much things to get.