For a first movie, the artwork is impeccable.
Some parts of the animation need a few more frames to make them look natural, i.e. breath movements, moving hair... It looks unnatural if they just stayed put like that.
Also, try doing the same for those scenes of Cloud, Sephiroth, Terra, Ventus, Aqua etc... when they are shown on screen for like one second or two. Because those parts look like still images, and that makes the production a little sloppy.
Still, great job!