For a long time Nintendo's Shigeru Miyamoto has wanted to make a multiplayer Mario game. Now it's possible with New Super Mario Bros. Wii, thanks to "the graphical capacity of Wii console"...
"It was all thanks to the graphical capacity of Wii console. If two players or more are simultaneously controlling Mario and Luigi in the same screen on a platformer game, the slower player will be left behind by the faster player, beyond the game screen. This time the screen zooms in and out accordingly, thanks to the capacity of the Wii console. The camera can zoom out as far as three times wider where you can see a very small Mario running around, and zoom in to show huge Mario and Luigi. The camera will work automatically and simultaneously, according to the position of four players. That’s how we realized a Mario game which can be played by up to four players at the same time."
Miyamoto also believes the multiplayer mode helps balance the game for different skill levels.
"If there is one veteran player among four players, he or she can lead the other three and they don’t have to do much. People can enjoy a kind of play like peeking inside Bowser’s castle to see how scary it is."