Pretty darn good but there's always room right?
I have to admit that I don't think it needs a massively descriptive background story. The mystery in just watching a story unfold that one knows nothing about is a perfect story. Mystery is a good dramatic tension.
Things to work on though (As this is a review):
1- The initial loading bar needs to be a little more obvious. I was sitting at my screen wondering if it was done because it wasn't saying "Ready" or "Play" anywhere. If a viewer is confused about something as simple as that it needs fixing.
2- Seriously dude THE FLASHING! If you're not going to re-do this animation and take out some of or lesson the strength of the flashes at least put a warning in your comments or before it starts because there could be people on the floor having an epileptic seizure. You really have to think about what people could be watching this not just you.
Ok that's all form me