Hmmmm...
Personally I think that slightly fuzzy sprites look better than tiny sprites that are hard to see, but that's just me. I use a program called GIMP to give my sprites a transparent background, and it's really easy. Perhaps you can use that for future sprites? ;)
Besides the text, and the fact that the sprites were tiny, and the lack of a background, one thing that could be improved in the future would be to make it less repetitive. You don't want the viewer to get bored with the same thing happening over and over.