(also known as Sonic Pocket Adventure) is a platform game developed by SNK and released for the Neo Geo Pocket Color in 1999. The game is based on Sonic the Hedgehog 2 (1992) for the Sega Genesis, borrowing much of the stage themes and gameplay elements, but featuring unique stage layouts, elements from other Genesis Sonic the Hedgehog games, and extra game modes. Sega's Yuji Naka and the rest of Sonic Team supervised over production. The game was released in December 1999 to positive reviews. Critics felt Sonic Pocket Adventure was a faithful adaptation of the traditional Sonic game formula, most importantly not making any sacrifices to the game's speed. Reviewers praised the game as one of the best among the Neo Geo Pocket Color's library and commended the quality of SNK's hardware. Several members of the SNK development team later formed Dimps which went on to develop several more Sonic games for handheld devices. Gameplay Sonic the Hedgehog Pocket Adventure is a platform game in the style of the classic Sonic the Hedgehog games for the Sega Genesis. The game is heavily based on Sonic the Hedgehog 2 (1992) for the Genesis, while also using concepts from Sonic the Hedgehog (1991) and Sonic the Hedgehog 3 (1994). Sonic 2'''s stage themes are featured throughout, but the stage layouts are unique to the game. The bonus stages are also borrowed from Sonic 2. AllGame called the game "a slightly dumbed down port" of Sonic 2 and Official Dreamcast Magazine called it "essentially an adaptation of Sonic 2." Unlike Sonic 2, Sonic Pocket Adventure features some exclusive modes. The game includes a save feature so the player can replay any level they have previously completed. There is also a time trial mode which ranks the player based on how quickly they finish each level. Another time trial mode requires the player to finish with 50 or more rings for the time to count. Sonic Pocket Adventure also supports two competitive two-player modes with the use of a Neo Geo Pocket link cable. One mode has the players racing each other to finish the stage first, while the other is a race to collect a target amount of rings. The second player controls Tails. There is also a puzzle mode where the player assembles portraits of Sonic characters using hidden puzzle pieces found within the levels. Completing the puzzles unlocks a sound