No you can't, there has to be a floor/platform (even if two very small ones, love it when I see computers spawn and fail to jump on the platforms and die, lol.)
I, like many of you out there, don't care about reviews for games I will definitely get. So whatever score or/and comments Smash receives from reviewers don't matter. It's the fact that I love the game and enjoy playing it that matters.
Like Mario Party. They keep getting bad reviews "more of the same" etc...but I don't care, I still buy the game and love playing them with my family