Not terrible, but it just doesn't seem that impressive to me. The very beginning segment of the movie was very boring to watch; something other than single closeups might have been better, possibly some shots of the scenery. Your spriting at least moves as it should with no wrongly-placed frames despite a few instances of areas in need of touch-ups (the scene using Silver could use improvement, your other supporting cast are just...there?), but this is also way too long to use for an opening sequence. This is more along the lines of a preview, so if you are going to add an intro to your work, consider condensing the intro theme, and cut out the filler. Watching this felt like it was being dragged out with nothing really going on, while some of the scenes only seemed there to fill time.
As for your custom sprite designs, I'm not liking them too much. I know from experience how difficult it is to make an appealing fan-character, but your purple dude is way hard on the eyes. However, I'm nagging.
Try to add some more punch to your next project's execution. 4.5 / 10