Sonic 2

is a 1992 platform game developed by Sega Technical Institute (STI) for the Sega Genesis. Players control Sonic as he attempts to stop Doctor Robotnik from stealing the Chaos Emeralds to power his space station, the Death Egg. Like the first ''Sonic the Hedgehog'' (1991), players traverse side-scrolling levels at high speeds while collecting rings, defeating enemies, and fighting bosses. ''Sonic 2'' introduces Sonic's sidekick Miles "Tails" Prower and features faster gameplay, larger levels, a multiplayer mode, and special stages featuring pre-rendered 3D graphics.

After ''Sonic the Hedgehog'' greatly increased the popularity of the Genesis in North America, Sega directed STI's founder, Mark Cerny, to start ''Sonic 2'' in November 1991. Members of Sonic Team—including the programmer Yuji Naka and the designer Hirokazu Yasuhara—moved from Japan to California to join the project. ''Sonic 2'' was intended to be faster and more ambitious than the first game. The development suffered setbacks, including cultural differences between the Japanese and American staff, and numerous levels were cut due to time constraints and quality concerns. As with the first game, Masato Nakamura, a member of the J-pop band Dreams Come True, composed the soundtrack.

''Sonic 2'' was widely anticipated, and Sega backed it with an aggressive marketing campaign. It was released in November 1992 to acclaim and received numerous year-end accolades, including two Golden Joystick Awards. Critics considered ''Sonic 2'' an improvement over the first game and praised the visuals, level design, gameplay, and music, but criticized the low difficulty level and similarities to its predecessor. ''Sonic 2'' grossed over and sold six million copies by 2006, making it the second-bestselling Genesis game behind the original ''Sonic the Hedgehog''.

''Sonic 2'' solidified ''Sonic'' as a major franchise and helped keep Sega competitive during the console wars of the 16-bit era in the early 1990s. It continues to receive acclaim and is considered one of the greatest video games of all time. ''Sonic the Hedgehog 3'' and ''Sonic & Knuckles'' followed in 1994. ''Sonic 2'' has been rereleased on various platforms via compilations and emulation; a remake was released for Android and iOS in 2013 and ported to consoles in the compilation ''Sonic Origins'' in 2022. A number of ''Sonic 2'' prototypes have leaked since the release; the first, discovered in 1999, played a significant role in the development of a game datamining community.

Gameplay

''Sonic the Hedgehog 2'' is a side-scrolling platform game. It features a story similar to the first ''Sonic the Hedgehog'' (1991): Doctor Robotnik, a mad scientist, seeks the Chaos Emeralds to power his space station, the Death Egg, and traps the animal inhabitants of West Side Island in aggressive robots. As Sonic the Hedgehog, the player embarks on a journey to collect the Chaos Emeralds and stop Robotnik. The player character can run, jump, crouch, and attack by curling into a ball. ''Sonic 2'' introduces the spin dash, which allows the player to curl while stationary for a speed boost, and Miles "Tails" Prower, a fox with two tails who acts as Sonic's sidekick. In the default single-player game mode, the player controls Sonic and Tails simultaneously; a second player can join in at any time and control Tails separately. The player can also choose to play as Sonic or Tails individually.

The game takes place across 11 zones with 20 levels ("acts"). The acts are larger than the first game's, and the player navigates them at high speeds while jumping between platforms, defeating robot enemies, and avoiding obstacles. Springs, slopes, bottomless pits, and vertical loops fill acts, as do hazards like water and spikes. The player passes checkpoints to save progress. The last act of each zone ends with a boss battle against Robotnik. ''Sonic 2'' features twice as many unique level themes compared to the first game, and most zones end after two acts rather than three.

The player collects rings as a form of health: if they have at least one ring when they collide with an enemy or obstacle, they will survive, but their rings will scatter and blink before disappearing. The player starts with three lives, which they lose if they are hit without a ring, fall down a pit, get crushed, drown, or reach the 10-minute time limit; they receive a game over if they run out. Power-ups like shields and invincibility