It's ok.
For one I'm not a huge fan of the song. So take that as you will.
I'm not very impressed with the whole project, regardless. I'll give you my Pros and Cons:
Pros:
+A slick presentation
+A nice blend of 'real' graphics with your animation
+A semi-cohesive story... not many NG movies can say that
Cons:
-The art style just doesn't jive with me. It's consistent... so that's a plus, but it's annoying. The stupid over-exagerated mouths, eyes, and expressions scream of both anime (which I like) and cutting corners (which I don't like). Here, however, I can cut you some slack because I know the presentation is supposed to be whimsical and light-hearted. Granted. However, these expressions are just to cliche and bogged down by being associated with all the other crap that looks the same.
-The animation, I think, is lazy. Those reused legs for running (outside the school)... I noticed that! Also, all the cheap anime-esque "flailing legs" and "waving arms" were just bland and overused. However, I can tell you some parts were very good, though the art style itself is oversimplified in my opinion. There IS still some good here.
-Though presented well, I'll always prefer well drawn, hand-drawn images... a cohesive art style throughout. You did an admirable job mixing the two, but I just don't think it's that effective. The pictures helped your background be more elaborate, but when you said you were working on backgrounds, I think you dropped the quality on the other things.
All in all, I think it was an average movie, thus the 5. 10's are for flawless movies, which this is not. This movie just sort of left me feeling "Ok. That was nice."
It's really just a very typical story with nothing really new or exciting or clever... save some Directional uses of the background with the character.
Looking at this a second time, it's a neat use of backgrounds with the quick transitions... but that, at best, is what is successful... which I don't think is saying too much.
Would NG be a worse place with movies like this? No... I think this is better than most. But it takes more than just this to be good (as I've commented on above). Her dancing to music or events is what people do when into music.. so that's cool, I guess.
Branch out more and come up with something more whimsical. Again, this was just average with a lot of cliche conventions and an uninspiring story.
Keep working hard, you have the raw materials to do good things.