Sonic & Knuckles (Sega Genesis, 1997)

Sonic and Knuckles is an excellent game starring not just sonic but the crimson curmudgeon Knuckles. Well actually I don't know if he's a curmudgeon, but he is definitely ill-tempered at times. Anyways playing as Knuckles is a very unique and refreshing spin on playing a Sonic game. Knuckles doesn't just spin attack like Sonic but he also can glide and climb vertical surfaces! I don't know about you but in the days of 16 bit gaming there weren't many characters who could do that besides Ryu and Strider. Even better is that this game is compatible with Sonic 2 and 3! How? Well this game cartridge was designed so that you can flip the top open and slam a game on top of it. Just don't put anything besides Sonic 2 and 3 in there. Anyways once you do that, you can play Sonic 2 and 3 with Knuckles. It's actually a pretty awesome experience. This is one of those rare instances where Sega got it right with a gaming add-on. Check it out sometime.