Brilliant.
The pre-loader, whilst it looks great, really needs a loading bar. Maybe you could have the purple bar slowly increase it's height until it fills the screen? After loading, a play button rather than an automatic start would be nice.
Also, there's a bit of slowdown in the bit where the 2 children are walking along and you see a couple of slices of earth. Maybe you should make the slices of earth less complex?
Also, setting the music to 'stream' would ensure that it remained in synch no matter the quality, as the player would drop frames of animation if necessary.
However, that's where the criticisms (small ones at that) end.
The music was great - enjoyable to listen to and suited well to the other-worldly landscape.
Your graphics are very simple (specially those of the characters) but they look great and I love your colour schemes (specially the purple ;)) and the parallax scrolling you use. I also really like the pools of light and the bit where you see the ball go down the steps. I also really like the part where you see the city lights turn on and the design of the water machine.
The animation of the characters is rather simplistic, and the part where the blue creatures advance on the pale-blue child does look really unconvincing. However, it perhaps works better than a frame by frame animation would have as it keeps to the overall style.
The story was wonderful. Despite the lack of speech (textual or spoken) you gave the cast a bit of character. The shapes you used for the eyes to express emotions worked brilliantly.
Whilst simple at heart, it was the way you paced the introduction of each element that made it work so well. The appearance of 2 red eyes, cliched as it is, worked well as did the increasing number of blue things visible through the holes.
It was the ending that made this movie. Our perceptions of the 2 races was turned on its head by the (slightly chilling) conclusion and a few parallels can be drawn with real life. However, these are left to us to think about and ponder, rather than being overtly pointed out or getting in the way of the story.
Working well as an enjoyable story, a feast for the eyes and as a parable, I think this has earned a 10 - a score which I rarely give out.
Congratulations.
You deserve it.