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 CD
The 1991 release of "Sonic the Hedgehog", the first game in the "Sonic" series, was a major commercial success and positioned Sega as Nintendo's main rival in the console market. Lead programmer Yuji Naka, dissatisfied with Sega of Japan's rigid corporate policies, moved with several members of Sonic Team to the United States to develop "Sonic the Hedgehog 2" with Sega Technical Institute (STI). Meanwhile, Sega planned to release the Sega CD add-on for its Genesis, and wanted a "Sonic" sequel that would demonstrate its more advanced features. Sonic's character designer Naoto Ohshima was "Sonic CD"s director; the remainder of the team comprised Sega staff who had developed "The Revenge of Shinobi", "Golden Axe 2", and "Streets of Rage".