Very nice
So what if it was a test? I think the response it has received is a good indicator of the success of that test. And remember that the secret behind creativity is hiding your sources. It does not mater how you put together the art (as long as its legal), all that maters is that you are able to put together what you intended to.
I see animations like this and it reminds me of back in the day when I could animate. I remember that I tended to rush through things, and when I forced myself to take my time, my work was much better. You should consider it. With a little focus, you could make some amazing work.
I agree with the other reviews that say the NG logo was a mood killer, and the one top down scene was very out of place. Otherwise, everything was fine. The story was a great idea. Interesting enough that I could imagine writing a whole series around it. Girl dies, comes back and tries to make things work, they obviously don't because she is DEAD, story peaks when she gets him killed so they can be together, but ends in tragedy when he discovers she did it intentionally. Just a thought.
Anyway, keep it up.