The original Mega Drive/Genesis version of "Sonic the Hedgehog 2" sold more than six million copies worldwide, making it the second best-selling Genesis game behind the original "Sonic the Hedgehog". Cited as one of the greatest video games of all time, it received critical acclaim for its level design, visuals and music. It has been rereleased on various platforms; a remastered version developed using the Retro Engine released on iOS and Android in December 2013. Two sequels, "Sonic the Hedgehog 3" and "Sonic & Knuckles", were released in 1994.