Some suggestions
Well, I liked the idea, but I think you cut it too short. Maybe some more conversation between the Magikoopas would have been fun. Also, if you can't get recorded dialogue, please don't have the text so high up. I'd suggest using subtitles instead.
Oh, and more fight scenes! And... did you need to show that much of the castle all the time?
I will give this a 4. Keep working at animating, and soon you'll get 5's. I think your talent is quite promising.