Simplicity is the ultimate sophistication. This film absolutely nailed that. Despite simple plot, characters, throughout the story telling it become something more and more.
It also very well done in term of presentation, when character is angry you felt that, when character is sad you felt that despite lacking in character progress or build up you still able to relate.
When the film end it left you with so much though and brilliantly it open to many interpretation. Brilliant movie but might no be for everyone.