Sonic and Knuckles is one of the greatest games ever. It's level design and soundtrack are vast improvements on the already great designs and music of 3. Also, it's surprisingly inventive, and not redundant since it uses the same special stages and gameplay as 3. Not only that, the game allows Sonic 3 to be put in, so that Sonic and Tails can play through 3 and straight into Sonic & Knuckles while finding ways to improve on the Chaos Emeralds and turn them into something new, creating new story elements unavailable in one cartridge! Sega's unbelievabe. Sonic 2 can also be put in it to let you play as Knuckles through Sonic 2! It's amazing, it really is. I recommend this for anyone. Sega Genesis is popular because of games like this.
