Super Mario 128 is a name of a series of projects that were to be used to create a Super Mario 64 sequel. What was displayed at Nintendo Space World were the rapid generation techniques later used in Pikmin, and the "sphere-walking" technology seen in Super Mario Galaxy and The Legend of Zelda: Twilight Princess. Other aspects include physics technology which was later used in Metroid Prime and Super Mario Galaxy 2.
Super Mario 64 2 Edit
A rumored expansion and sequel to Super Mario 64 called Super Mario 64 2 was said to be developed on the Nintendo 64DD, but ended up being cancelled. Shigeru Miyamoto mentioned at E3's 1997 convention that he was "just getting started" on the project. In a Nintendo Power interview with Shigeru Miyamoto in November 1999, Miyamoto said, "Well, for over a year now at my desk, a prototype program of Mario and Luigi has been running on my monitor. We've been thinking about the game, and it may be something that could work on a completely new game system." The game only had a demo of one level made for it, and nothing was done beyond that. Miyamoto claimed that multiplayer was the first aspect of the game that he wanted to include. Rumor has it that elements from Super Mario 64 2 were eventually transferred over to Super Mario Sunshine, Super Mario 64 DS, and New Super Mario Bros..
In an interview in the September 2006 issue of Nintendo Dream, Miyamoto answered some questions about Mario 64 2, stating that he had forgotten whether it was being made for the Nintendo 64DD, and that "it's become other games". When asked whether he meant that the game systems are being used in other titles, Miyamoto responded, "From the time that we were originally making Mario 64, Mario and Luigi were moving together. But we couldn't get it working in the form of a game," echoing his statements from 1999.
Super Mario 128 Edit
The name Super Mario 128 was first used by Shigeru Miyamoto during an interview for Nintendo Power as early as January 1997, as a possible name for a Super Mario 64 sequel:
Super Mario 128 was referred to again at the SpaceWorld event in August 2000, when Nintendo showed a technology demo titled Super Mario 128 to display the power behind their then-upcoming Nintendo GameCube game console. In the demo, a large 2D Mario split off into 128 smaller Marios across a kind of circular board. The demo went on to display the technical power of the GameCube by rendering additional Marios at once until the number of characters on the screen reached 128. The terrain in the demo was manipulated, rotated, and spun to show the physics abilities of the system.
One year later, at SpaceWorld 2001, Super Mario Sunshine was unveiled as the next Mario game; it was released in July 2002 in Japan and a month later in North America. In an interview after E3 with Computer and Video Games, Miyamoto confirmed that Super Mario 128 and Super Mario Sunshine were separate games.
During the GDC 2007, Miyamoto mentioned that Super Mario 128 was merely a demonstration to illustrate the power of the GameCube. He also stated that most of the elements of Super Mario 128 were incorporated into Pikmin, in that the player controlled a large number of characters on screen. Other elements such as walking on 3D spheres are seen in Super Mario Galaxy.