Classic Game Room presents a CGR Undertow video game review of Sonic & Knuckles for the Sega Genesis. As Sonic 3 was released without all the content and features it was originally intended to include, Sega followed up quickly with the release of Sonic & Knuckles in 1994. Utilizing a rarely seen cartridge technology, it was the first and only officially licensed lock-on cart that allowed for previous Sonic games to be plugged into it and expand their original content, most notably the chance to play as Knuckles the Echidna. As a stand-alone game it's not much different from Sonic 3, but adds plenty of new features and platforming gameplay variety to continue Sonic's 16-bit legacy. This review features Sonic & Knuckles gameplay footage and commentary from CGR Undertow reviewer Kevin.