Super Mario 128

Super Mario 128 was a codename for two different development projects at Nintendo. The name was first used in 1997 for a sequel to Super Mario 64 for the 64DD, which was canceled. The name was reused for a GameCube tech demo at the Nintendo Space World trade show in 2000. Nintendo gradually incorporated the demonstrated graphics and physics concepts into the rapid object generation of Pikmin (2001), the physics of Metroid Prime (2002), and the sphere walking technology of The Legend of Zelda: Twilight Princess (2006) and Super Mario Galaxy (2007). The Super Mario 128 demo intrigued widespread analysis, rumors, and anticipation in the media throughout the 2000s.

Super Mario 64 2
The name Super Mario 128 was first used as early as January 1997 by Shigeru Miyamoto, as a possible name for a Super Mario 64 sequel. This rumored expansion and sequel to Super Mario 64 called Super Mario 64 2 was said to be developed for the Nintendo 64DD, but was canceled due to the Nintendo 64DD's commercial failure. Miyamoto mentioned at E3's August 1997 convention that he was "just getting started" on the project. At Nintendo's Space World 1997 trade show in November 1997, Miyamoto added "We haven't decided [whether it's two-player] yet. We are currently working with a system where Mario and Luigi can co-exist, and they are both controllable by the player. But we will decide more game elements when we finish everything about Zelda."

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 had only a demo of one level made for it. Miyamoto claimed that multiplayer functionality was the first aspect of the game that he wanted to include.

Miyamoto had considered the two next frontiers of the Super Mario series to be a gameplay mechanic of walking on a rotating sphere, and coincidentally a setting in space, it took a long time to find a way to resonate these ideas with the production team. He loved the novel idea of sphere walking, because it was totally unexplored in the game industry, and because focusing on a full sphere can eliminate camera movements and thus motion sickness. He learned greatly from the world's adaptation to the 3D gameplay of Super Mario 64 and he briefly experimented with rolling fields during the development of Paper Mario (2000) for Nintendo 64. During the development of Doshin the Giant for Nintendo 64, he eagerly proposed that it could become the first sphere walking game but the staff rejected such an exceedingly massive development for the game which was released in December 1999.

GameCube demo
The name Super Mario 128 gained permanent fame when reused for a new technology demonstration at the Space World event on August 24-26, 2000. This software was controlled by staff to show new gameplay mechanics and the processing power of the upcoming GameCube game console. Development of the demo was directed by Yoshiaki Koizumi, who would later become the director of Super Mario Galaxy. In the demo, a large 2D Mario spawned increasing numbers of smaller Mario figures, independently walking across a circular board, until the number of onscreen characters reached 128. The terrain in the demo was manipulated, rotated, and spun like a floppy saucer to show the physics engine software. GamePro declared Super Mario 128 to be one of the 15 most anticipated games of 2001. Regarding Nintendo's secrecy and lack of elaborate demonstration of the camera system, GamePro assumed that "The precautions are warranted as developer after developer aped the exact camera mechanism from Mario 64 for their titles."

Koizumi said he spent much thought after the event about the "close to impossible" undertaking of productizing Super Mario 128 as demonstrated. Combining that demo's rounded surface with Mario's need to freely roam, Koizumi's next imagined groundbreaking objective was to demonstrate Mario walking upon a gravitational sphere. To even be able to attempt that, would require tremendous technological expertise, motivation, and achievement from a dedicated team and would not be undertaken until 2003.

There had always been distinctly separate development of Super Mario 128 and Super Mario Sunshine, which Miyamoto considered to be similar to Super Mario 64 anyway. He said, "obviously we were doing work on the Mario 128 demo that we were showing at Space World, and separately we were doing work on experiments that we made into Mario Sunshine." At Space World 2001, Super Mario Sunshine was unveiled as the next in the Mario series, released in 2002.

Nintendo commemorated the height of Super Mario 128 hype in the 2001 GameCube game Super Smash Bros. Melee with a battle stage titled "Super Mario 128", where the player is assailed by a total of 128 tiny Mario figurines.

Resurfacing
In 2002, Miyamoto predicted that Super Mario 128 would let players "feel the newness that was missing" from Super Mario Sunshine because he thought of that game as more of a revisitation of Super Mario 64.

Rumors said that the reason for Nintendo not having shown Super Mario 128 at E3 2003 was because the game was extraordinarily innovative and Nintendo did not want other developers stealing the ideas from the game, some had assumed about the Space World 2000 show. However, Miyamoto later confirmed that Super Mario 128 was still in development and that the development team had planned to take the Mario series in a new direction.

In 2003, Nintendo's George Harrison stated that Super Mario 128 may not appear on Nintendo GameCube at all. Yoshiaki Koizumi, who had directed the original Super Mario 128 demonstration, joined Nintendo's new EAD Tokyo office. There, Shigeru Miyamoto pushed him to hold a much bigger vision for the next Mario series game and Koizumi said this: "By working on [Donkey Kong Jungle Beat] together, I got to know the staff well enough by then, and I thought, if it was with this team, we may just be able to tackle the new and difficult challenge of making spherical platforms work." There at EAD in 2003, Koizumi's team began working on prototypical spherical platforms in an intensive three-month process of iterative demonstrations for Shigeru Miyamoto. Nintendo's President Satoru Iwata requested Miyamoto's singular signature effort to turn this product, which would become Super Mario Galaxy, into a showcase for the Wii.