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 the Hedgehog (8-bit video game)
Porting the original game to the 8-bit hardware was impossible, so Ancient built their "Sonic" from scratch. The team decided to make their version completely different from its Genesis counterpart. According to Koshiro, the game had three phases of development. In the first phase, Ancient developed the game with the Genesis version in mind. The second and third phases were largely Ancient's own ideas, with Sega supervising their work. Koshiro thought reinventing "Sonic" for 8-bit hardware was challenging, as he did not work at Sega and had never developed a game before. However, Sega had faith in him because of his relationship to the company. Koshiro composed the soundtrack and sought to retain the feel of the Genesis version. He converted Masato Nakamura's 16-bit "Sonic" score to the 8-bit programmable sound generator to start, but ended up using only three of those tracks; the remainder of the music is Koshiro's work.