It's one of the best sprite animations I've seen..
...that doesn't mean it's marvellous but it's certainly above average for it's genre.
If you were to get rid of the white pixels outlining some of the sprites, add some sound effects, explain how the hell Mario just randomly started flying and most importantly, work at a much higher frame rate, then this would be a pretty damn good little toon.
As it is it's okay, but nothing special. Keep the work coming though, practice makes perfect and all that and you definately have potential.