It has 25 charcters including unlockable characters.  With modes like Adventure, Classic and All-Star, plus great multiplayer action, Super Smash Bros. is super fun!

 

UPDATE: Just Announced - Super Smash Bros. 3 will be hitting shelves for the Nintendo Revolution sometime in June 2006!  We will be doing updates on this sight when it comes out (unless we are too busy playing the game!)