Really good animation...
It was very well drawn in the style it was in, and the animation was smooth for the most part. The chronology flowed well without skipping around too much or leaving too much out to make you wonder what was going on.
The only thing I wouldn't be too proud of is the 600+ layers. Unless you counted across all of the separate scenes in your movie, it makes me think you simply don't know how to use scenes. You should really look into it. It could save you TONS of headaches in having to scroll through the hundreds of layers you say you had. Ignore this if the movie WAS separated into scenes... but if it was all created in one time-line... whoa.