not bad...
but this must be one of the first movies you made. I noticed that you are suffering from what I call "black box syndrom", where all your sprites have black boxes around them. to fix this, select the sprite, if it has a blue border,
goto edit/ungroup, the image should now have a gray border. with the new gray border, or if it has a gray border to begin with, goto edit/trace bitmap..., a window will pop up, change the two numbers to "1", set the curve fit to pixles, and the other scroll box to many courners. this will make every pixel its own shape, that way you can select the surrounding "black box" and delete it.
You got the potential, you just need to learn some more skills. good luck.