I've got some sweet ideas for a sequel. First, some of the new characters: Wario, King K. Rool, Diddy, Ditto (turns into characters already in the fight, otherwise just Pikachu), Mouser, Birdo, and the Hammer Bros., which I would call Spike and Mallet (they're like the ice climbers but they stick closer together and use team-up attacks).
New levels: K. Rool's ship and Race 2 the finish... in Giga Bowser's castle!
New items: Kuribo's shoe!!!
I've got plenty more but those are my favorite ideas.
"Kids, don''t use formula one race cars to chase hedgehogs."