It's good. Not great.
To be honest, it seems more like just a Kingdom Hearts animation. Off of a Kingdom Hearts scene.
Here are my suggestions:
1. Original sprites
2. Sprites breathing, making them go up and down, so they don't look like just blocks sitting there
3. Better text, looks very plain.
4. Make the intro more lively
5. Make intro buttons more lively, they are just basically rectangles with text. Make Keys or Keyholes or something that has to do with the plot.
6. The music just STOPS if you watch it for a while, so you may want to fix that. Loop it maybe.
It has potential, but definitely make some original sprites.