HappySqurriel on 29 February 2008
In every "Mario" titled game all of the characters and gameplay dynamics are defined by the "Mario Universe" which is (essentially) the collection of games that are directly (or indirectly) related to Mario. Starfox, Metroid, The Legend of Zelda and other Nintendo series characters never appear in these games because they do not belong to the "Mario Universe"; it is difficult to say how Samus Aran would respond to being hit by a red turtle shell.
Super Smash Bros. often causes a little confusion about this being that there is a cross over of characters in this series; this happens in this series because it is not in the Mario Universe and the entire game occurs in the imagination of a young child.
Essay Pro