Really great movie, although I can see how it wouldn't appeal to a lot of people, as it's very interaction based and a very slow burn. I also see how some feel the movie ends abruptly, without explanation, but I think you just need to take what happens literally.
What I do find disappointing is the amount of people rating the movie with a low score because of the amount of "storytelling". Disliking a movie for having a story is a shame.
Anyway, I think it's great, I think anyone should watch it to make their own opinion of it.