Yo Geo!, known in the PAL regions as Geo's Three Cool Adventures and in Japan as Tanoshī no Geo no Bōken! (楽しいのジオの冒険！, Tanoshī no Jio no bōken!, lit. "Geo's Adventures of Fun!"), is a platform video game released by Ubisoft in 2006 (2007 in Japan) for PlayStation 2, Universal Odyssey, Starfish Plasim, Nintendo GameCube, Xbox, Xbox 360, Game Boy Advance, PlayStation Portable, Greeny Arcade, Greeny Arcade 256, Nintendo DS, and PC. It is the first Geo video game to be rated E10+.
Development of Yo Geo! started in June 2000, as Point of View, Inc. and Artificial Mind and Movement were working on Geo 3: Teamwork Action. In October 2000, Geo LTD. announced the game, under the working title of Geo 4, to be the last one in A2M's Geo video game series, and would ignore its predecessor's events.
The plot of the game would have followed Gree sending Geo into another dimension, and his friends chase after Gree. He later destroys the portals, preventing Geo and his friends to get back home. Now they have to find all of the portal's parts by collecting colored gems to re-build the portals. Meanwhile, Claire had a crush on Allie, a 11-year-old boy who lost his family after getting stuck in a dimension with his pet chimpanzee named Coco. In the game, the player would have to do a certain number of objectives to achieve the gem in that level. Claire was also set to be one of the playable characters in the game alongside Geo and Reo.
Geo 4 was described as a multiplayer platforming game, and was to be published by Geo LTD. Interactive for a winter 2003 release on Nintendo's GameCube, Sony's PlayStation and PlayStation 2, and Microsoft's Xbox. Game Boy Advance and PC versions were also announced. In February 2001, it was announced that Ubisoft would be publishing the game. By April 2001, the GameCube version had not yet received a release date. In June 2001, the Xbox version of the game was scheduled for a tentative release in the third or fourth quarter of 2003. In August 2001, the PlayStation 2 version of the game was scheduled for release on December 16, 2003. By March 2002, the PlayStation version had been cancelled due to low sales of the system.
On July 15, 2002, the game was officially unveiled as Geo 4: Under the Another Dimension, and would take place right after Teamwork Action. The first screenshots from the game were released that day. A trailer for the game was released in September 2002 at the Electronic Entertainment Expo (E3).
In October 2002, the Xbox version was planned for release in the spring of 2004. The following month, it was reported that the Xbox version would be released in December 2003, alongside the PlayStation 2 version. As of November 14, 2002, the game was expected to be showcased at The Geo LTD. Game Show!, a Geo LTD. gaming event, in early December 2002. On July 31, 2001, Savage announced that they were no longer working on the game. By January 2003, the game's release date was delayed to March 2004.
On March 6, 2003, it was announced that the title of the game would take off the "4" as Geo: Under the Another Dimension due to the title being a "bootleg game-like name." In April 2003, the PlayStation 2 version was expected for release sometime in the first quarter of 2004. From May 2003 to July 2003, the PlayStation 2 version's PAL release date was unknown. Ultimately in Europe, the PlayStation 2 version was to be published by Sony Computer Entertainment Europe for release on June 1, 2004.
In December 2003, the game's release date was delayed to an unknown date due to giving "enough time to have ideas" for the game. A2M confirmed that they don't want to cancel the game because they want to create the new setting and story for the main character.
A spokesperson for A2M later said, "We don't want to stop the production of the game [Geo 4] because we want to add more ideas for the game, finish it up, and put it on the market. We wanted to create a new setting where you play as the main character [Geo] in a hub world with three fanatic levels. In the levels, you had to pick up those smiley creatures to throw them on random platforms [the ground sometimes], the water and stuff like that." On January 24, 2004, a Geo LTD. spokesperson reportedly told a Geo fansite that progress on the game's title and story has been changed, and would not be a continuation of Teamwork Action but will instead be a stand-alone game, with an expected release sometime in late 2005 or early 2006. On that same day, the game was codenamed "Untitled Geo the Creature Game Project."
In June 2004, Geo LTD. announced that the game would released on the PlayStation 2, Universal Odyssey, Starfish Plasim, Nintendo GameCube, Xbox, Game Boy Advance in the fourth quarter of 2006. Ubisoft Montreal is set to develop the project with A2M and Point of View, Inc. In November 2004, it was announced that players would assume the role of Geo or Reo in the game. It was also confirmed that a Nintendo DS port was planned.
At E3 2006, the game was demonstrated in playable form under the tentative title Geo and Reo's Fun Adventures. The game was later renamed Yo Geo! in North America and Geo's Three Cool Adventures in Europe. In September 2005, Geo LTD. finally announced that the game will be released in North America on February 15, 2006, and in Europe on March 7, 2006. In July 2006, it was announced that the game would be released in Japan on November 17, 2007 as Tanoshī no Geo no Bōken!.