This stage looks fantastic. I love the concept. I hope the planet goes all the way around, with two direct (and intriguing) gameplay implications: first, that players could only be KO'd UP. Technically you could hit someone to the side, but no matter where they are sent flying, it's "up" relative to some part of the stage. Meteor smashes would probably be rendered completely useless as a means of KOing opponents. Second, players on the "bottom" of the planet would experience inverted controls to an extent -- from the top, hold 'right' long enough and you'll wind up on the bottom, moving 'left' from the player's perspective. What happens if you stop and start again from there? Will 'right' continue moving you clockwise, or will the direction be reversed to accomodate your perspective? This could make battling exactly on the left and right extremes very challenging.
Enticing stage design. Sakurai does it again.