Sonic 3 and Sonic & Knuckles sold a combined four million copies worldwide, placing them among the bestselling Genesis games. It was initially developed as an isometric game similar to what would eventually become Sonic 3D Blast (1996), but became a conventional 2D platform game due to time constraints.
See also: Sonic the Hedgehog 2 (film), Sonic the Hedgehog (film), Sonic the Hedgehog, Sonic & Knuckles, List of Sonic the Hedgehog video games, Sonic the Hedgehog (2006 video game).