What is that, Filio? The boss is a radar controlled queenbee, not a turtlemobile. :p
Also, I agree with Tyler52, there should be a bigger emphasis on the inside of the tower, in act 1 or 2. If the one Spherallic is doing is 2, then make the tower act 1. Something more like the Tower of the Gods stage in Windwaker. There will be plenty enough content to fill the cloud stage, we might as well have a change of pace and do a tower one.
Also, Tyler, don't be too self conscious about trying to make a song. Even if you don't end up making one featurable, as you're still a bit rough around the edges, you'll likely provide some valuable inspiration. But I imagine with some coaching, you could make somethign worthy of it, anyways.