Pretty good, could be better
I have to agree with a lot of the reviewers here. First off, the artwork and animation was beautiful. The story may be a little clichéd, but I enjoyed your take on it. The main parts you need to improve would be the pacing. Overall, this went too slow. I think that it would be a lot better if you took out all the pauses where the screen is just black and removed between 1/2 second and 1 second from the beginning and end of each clip. It's the end of the world -- it should be more intense. Also, I would agree that you need to explain why the protagonist killed the soldiers at the end. I can think of a reason why, but really it is the sort of thing you need to explain so that we as viewers can better understand your character.
I'd say this deserves 8/10. You've definitely got the art, music, and story down, you just need to work on the cinematography a bit.