Sonic Generations (ソニック ジェネレーションズ, Sonikku Jenerēshonzu?) is a 2011 platform video game in the Sonic the Hedgehog series, produced by Sonic Team for PlayStation 3, Xbox 360, Microsoft Windows and Nintendo 3DS. It celebrates the 20th anniversary of the original Sonic the Hedgehog game and was released by Sega in North America on November 1, 2011, in North America on November 4, 2011 for PC Download, November 4, 2011 in Europe, and in Japan on December 1, 2011.. It is the first Sonic game to feature stereoscopic 3D graphics.
In Japan, the two versions are given subtitles: the PS3/Xbox 360/PC version of the game is given Shiro no Jikū (白の時空?, lit. "White Spacetime") while the 3DS version is given Ao no Bōken (青の冒険?, lit. "Blue Adventure").
Modern Sonic and Classic Sonic must restore time and defeat the Time Eater.