Although there are war and SF elements in this movie they are only theatrical backdrops to what is in reality a story about life, whats important, the choices we make, the sacrifices and the regrets. That, although the world continues on a personal level life is short and very individual. If it has any message it is to grasp life's opportunities when they arise because you may not get a second chance. This is a much better movie than the average rating and would make an excellent piece for a classroom discussion for those who are about to start out in adulthood and the decisions that will shape theirs and potentially others lifes. Overall I found it a cleverly put together story.
