Mario fans hoping for a new Super Mario Galaxy game or an HD remake of the existing ones are going to get a little taste of what those games could be like when Super Smash Bros. for Wii U releases next year. The fourth Smash Bros. game is confirmed to include a stage based on the stellar two game sub-series. Game director Masahiro Sakurai announced the stage on MiiVerse, and he explained that gravity will pull you toward the center of the planet, meaning you will have to change up your tactics to succeed on this new stage.
I've always felt that Smash Bros. needed a Mario Galaxy stage given how gravity could be implemented to create an interesting battle arena and Nintendo has gone and done just that.
Source: miiverse.nintendo.net