Sonic the Hedgehog Pocket Adventure
In August 1999, SNK announced that they were collaborating with Sega to develop a "Sonic the Hedgehog" game for their Neo Geo Pocket Color handheld system. The game was developed by SNK, with supervision from Yuji Naka and Sonic Team at Sega. This marked the first time Sega was directly involved in the development of a "Sonic" game for a non-Sega platform. The team planned for "Sonic Pocket Adventure" to be a return to the classic 2D gameplay style found in the "Sonic" games on the Sega Genesis. In particular, many game design and visual elements are borrowed from "Sonic 2". The game's background music tracks are also 8-bit renditions of music from "Sonic 3". "Sonic Pocket Adventure" was released first in North America on December 4, 1999. SNK released a system bundle with the game included for the holiday season. The game was released in Japan two weeks later, and in Europe in February 2000.
Sonic Adventure
During the early 1990s, Sega was one of the most successful video game companies due to its Genesis console. Sales for the console were driven by the popularity of its flagship franchise of 2D platformers, "Sonic the Hedgehog". During this time, series co-creator Yuji Naka worked with Sega Technical Institute (STI) in the United States to develop "Sonic" games. After the completion of "Sonic & Knuckles" in 1994, Naka moved to work with Sonic Team in Japan. STI began developing "Sonic X-treme" for the Sega Saturn"," which would have been the first "Sonic the Hedgehog" game to feature full 3D gameplay. "X-treme" suffered a series of setbacks and was canceled in 1997. The cancellation is an important factor in the Saturn's commercial failure; without it, the system had no original "Sonic" platformer. Meanwhile, Naka and Sonic Team developed original Saturn games, such as "Nights into Dreams." Due to the series' relative lack of presence on the Saturn, according to "Retro Gamer", "[b]y mid-1997 Sonic had essentially been shuffled into the background... it was astonishing to see that just six years after his debut, Sonic was already retro."