I refrained from posting a review after seeing the movie for the first time so here I am, doing it after the second view:
Overall it is a very long movie, lasting for 3 hours, so you would expect it to have plenty of dead-times, which it does (you can easily take away one hour and not change the meanings).
Most of the action (or 90% of it) is condensed in a 30 minutes time frame (out of the 180 minutes).
To me, the genre was more like a Drama than SF, I felt emotional a couple of times during the movie the first time I saw it and the second time...