Not easy
Its difficult to do what you tried to do, and for that i give you points. Your drawings are far better than i could ever do so i give you points there too. The animation definately has room for improvement though. You should draw more instances of your characters so you dont need to use as many motion tweens, i think it would look nicer.
Or if you dont like that idea, you can always use sprites. Thats what i did for my short chrono trigger movie.