Every time I've seen this film I've been wowed by its use of sound, particularly because it was an early film of the sound era.  It gives you an eerie feeling to watch it, because in many places this is still a silent film.  Sound effects are added where they will have dramatic effect, but where they would be required for just an everyday reality, they're left out...it makes each noise--especially the "Peer Gynt" theme, which usually breaks a silence--that much more effective.  