Sonic Delta, also known as Sonic Delta 40 MB, Sonic Delta Next, and Sonic Delta Origins, is a Sonic the Hedgehog 3 & Knuckles ROM hack by Esrael Neto. The game serves to combine the entirety of the main four Sonic the Hedgehog titles from the Sega Mega Drive (Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 and Sonic & Knuckles) along with restoring various prototype elements that were seen in those game's respective prototypes.