 Development of "Sonic Colors" began in 2008, following the completion of "Sonic Unleashed".While they kept most of "Unleashed"s core gameplay elements, developers Sonic Team and Dimps decided to create an equal balance between speed and platforming similar to that of the games released for the Sega Genesis, in comparison to the straightforward gameplay of "Unleashed".Following requests by fans, the team also made the decision to make Sonic the only playable character, and to omit "gimmick" themes such as the swordplay mechanic used in the 2009 spin-off "Sonic and the Black Knight".