Sonic the Hedgehog (XBLA)

Sonic the Hedgehog is a 1991 platform game developed and published by Sega for the Sega Genesis. It was released in PAL regions on June 21, North America two days later on June 23 and in Japan the following month. The player controls Sonic, a hedgehog who can run at supersonic speeds. The story follows Sonic as he aims to foil the mad scientist Doctor Eggman's plans to seek the powerful Chaos Emeralds. The gameplay involves collecting rings as a form of health, and a simple control scheme, with jumping and attacking controlled by a single button.

Development began in 1990 when Sega ordered its developers to create a game featuring a mascot for the company. The developers chose a blue hedgehog designed by Naoto Ohshima after he won an internal character design contest, and named themselves Sonic Team to match their character. It uses a novel technique that allows Sonic's sprite to roll along curved scenery which was based on a concept by Oshima from 1989. Sonic the Hedgehog, designed for fast gameplay, was influenced by games by the Mario creator, Shigeru Miyamoto. The music was composed by Masato Nakamura, bassist of the J-pop band Dreams Come True.

Sonic the Hedgehog received positive reviews for its visuals, audio and gameplay and is widely considered one of the greatest video games. It sold over 40 million copies across all platforms, becoming one of the best-selling video games. On the Genesis, which it was bundled with, it sold over 15 million copies, making it the best-selling Genesis game. It established the Genesis as a key player in the 16-bit era and made it competitive with the Super NES. It has been ported to multiple systems and inspired several clones, a successful franchise, and adaptations into other media. Sonic the Hedgehog 2 was released in 1992.

Gameplay

Sonic the Hedgehog is a platform game where players control the titular character Sonic, who is tasked with defeating Doctor Robotnik and obtaining the six Chaos Emeralds. The game takes place from a side-scrolling perspective. He is capable of running at high speed through levels that include springs, slopes, bottomless pits and vertical loops. The levels are populated with robot enemies, inside which Dr. Eggman has trapped animals; destroying a robot frees the animal, but is not necessary to complete the game. His primary form of offense is a spin attack, in which he curls into a ball and spins his body, damaging enemies and certain obstacles upon collision. This may be performed by jumping or rolling.

Scattered around each level are gold rings that can grant Sonic protection from a single enemy or hazard as well as an extra life if 100 are collected. Also scattered throughout the level are canisters containing power-ups such as additional rings and temporary invincibility. Signposts act as checkpoints where Sonic can respawn after losing a life.

The game is split into six principal zones, followed by a short Final Zone. Each main zone has its own visual style, and while some enemies appear throughout, each zone has unique enemies and obstacles. Each main zone is split into three acts, all of which must be completed. At the end of each main zone's third act, the player confronts Dr. Eggman for a boss fight. For most of the fights, Eggman's vehicle is fitted with different weapons. After completing the sixth zone, the player continues to the single-level Final Zone for a last encounter with Eggman inside a large machine environment. A brief animation shows Sonic's return to the first zone, with animals liberated from Dr. Eggman.

Reaching the end of any zone's Act 1 or Act 2 with 50 rings will cause a large ring to appear through which Sonic can jump to enter a bonus stage. In them, Sonic is continually curled up in his Spin Attack animation, and bounces off the bumpers and walls of a fully rotating maze. In these levels, the player earns a number of continues for each multiple of 50 rings collected, but the main goal is to obtain the Chaos Emerald hidden within the maze. Colliding with any of the blocks marked "GOAL" ends the level.