LONG.
It's amazing how you manage to compress this huge movie into a small 3.5 MB file. Kudos on that.
I really liked your drawing style, and it's one of most original and creative styles I have seen on NG in recent memory. However, there were several sound issues and there were times when the music did not match the mood of the scene. Also, there were times I lost myself in the movie. The plot would change dramitically and I would fail to understand some parts. Keep in mind that some people, such as me, have never seen the original Back To The Future before.