Sonic & Knuckles

Sonic & Knuckles is a 1994 platform video game in the Sonic the Hedgehog series, developed by Sonic Team and the Sega Technical Institute for the Sega Genesis. In addition to being a standalone game, through a system dubbed "lock-on technology," Sonic & Knuckles acts as an expansion pack to both Sonic the Hedgehog 2 and Sonic the Hedgehog 3, the latter with which it was developed in tandem. The Virtual Console release of the game emulates this function: it will detect if the player has the other games in the Wii's memory, and provide the user with a menu to select which combination of games they wish to play.