Sonic the Hedgehog different media including animation, comic books, and a Hollywood film. The first "Sonic" game, "Sonic the Hedgehog", is a platform game released in 1991. Players control the anthropomorphic blue hedgehog Sonic, who can run and jump at high speeds using springs, ramps, and loops. Sonic must stop Dr. Robotnik from taking over the world using the Chaos Emeralds. "Sonic the Hedgehog 2" (1992) increased the overall size and speed of the series' gameplay and was the second best-selling Genesis game. It introduced Sonic's sidekick and best friend, Miles "Tails" Prower, who followed Sonic throughout the game, and allowed a second
Sonic the Hedgehog completely playable under a second player's control, as well as adding the option for players to utilize Tails' flying ability in levels. It also introduced the character, Knuckles the Echidna, who served as an additional antagonist with Doctor Robotnik for the game. "Sonic & Knuckles", another platform game in the "Sonic series", was released later in 1994. The game featured Knuckles as a playable character with gliding and wall climbing abilities and allowed gamers to plug in "Sonic the Hedgehog 3" to the top of the "Sonic and Knuckles" cartridge as part of the game's "lock on" functionality. This allowed