Sonic the Hedgehog (8-bit)

Sonic the Hedgehog is a platform game in the Sonic the Hedgehog series developed by Sonic Team in conjunction with Ancient. Published by Sega, the game was designed for the Master System and Game Gear video game consoles. It was originally released in December of 1991, in the Japanese (Game Gear version only), American and European markets. It is notable for being the last Master System game released in North America.

The game was re-released as part of Sonic Mega Collection Plus and was included as a hidden minigame in Sonic Adventure DX. Both of them are the Game Gear version.

Storyline
Sonic the Hedgehog battles Doctor Robotnik (Dr. Eggman in the Japanese version) for six Chaos Emeralds. When collected, those magical emeralds will allow Sonic to rid the world of pollution caused by Robotnik. Robotnik, however, has constructed a huge base on South Island and wants to now seize control of the world.

Gameplay
As in other games from the Sonic the Hedgehog series, the player controls the rapidly-moving Sonic the Hedgehog from a 3rd-person, side-scrolling perspective. The control and feel of the game is similar to that of its 16-bit successors, but with subtle differences such as graphical changes (the graphics of the original were adapted to suit the technical specifications of the GameGear) and waypoint markers positioned differently to the checkpoint markers of the original.

Sonic obtains rings which can be used as protection against enemy attacks. The maximum number of rings the character can hold is 99; when a hundredth ring is picked up, an extra life is awarded, and the ring count resets to zero. Unlike in other Sonic titles, the player cannot retrieve rings that are lost once Sonic is hit by an enemy. Probably that limitation was imposed due to the GameGear not being able to simultaneously render the numerous sprites required to depict large numbers of rings being scattered.

Chaos Emeralds, special collectible items, are found in secret areas in each of the six zones. Those "zones" are comparable to game "chapters" or "levels," each zone containing three acts, or levels of game play. The first two acts of each zone focus on standard side-scrolling game play, while the third act has no rings and is characterized by a boss fight. Special stages, accessed when Sonic has 50 or more rings at the end of an act, allow the player to collect Continues and Extra Lives.

Three of the zones were designed based on those from the 16-bit version of the game. A rarity in Sonic games, Bridge Zone Act 2 scrolls independently of Sonic’s progress, forcing the player to work at a fast pace. (However, that gameplay concept, where the character is forced across the level by an inalterable fixed-rate rightward scroll, was seen prominently in Super Mario World, a SNES game. Jungle Zone Act 2 is also different from traditional Sonic games, as the level map is vertical as opposed to horizontal.

Zones

 * Green Hill Zone (old zone): The first zone is different from the 16-bit version. The notable difference is that much of Act 2 is set underground in a series of caverns and also the background is different.
 * Bridge Zone: A zone consisting of a series of unstable bridges over a mountain lake. Act 2 features the aforementioned auto-scrolling background.
 * Jungle Zone: A colourful zone set deep in the lush rain forest. Sonic can run on logs to cross stretches of water. Act 2 is a vertical level where Sonic must scale a mighty waterfall.
 * Labyrinth Zone (old zone): Very similar to the MegaDrive version but with modified background music, creating a more sinister mood.
 * Scrap Brain Zone (old zone): Again, similar to the MegaDrive version with different background music. Teleporters replace the power chutes used in the 16-bit version.
 * Sky Base Zone: The final level is set aboard the first of Robotnik's many flying fortresses, rigged with a large number of sentry guns and lightning cables. The second Act is set on a giant airship with no rings, making it easy to be depleted of lives.

Differences between versions
The Game Gear version has a lower screen resolution, but a larger color palette. Sonic's sprite is smaller and the control is said to feel lighter (i.e. Sonic can accelerate and decelerate more easily, and can jump higher). In the first zone, warning signs were added near pits because the narrow screen and the high speed of the game do not give the players enough time to know what is ahead of them. The Jungle Zone Act 2 allows the player to fall below the level's bottom (as though into a bottomless pit) without losing a life, making this stage easier in the portable version. The Labyrinth Zone level design in the Game Gear version is significantly changed from the Master System edition: most notably, the Chaos Emerald is in an entirely different location, and all Chaos Emeralds are blue. Several bosses, including the final one, were modified from the Master System version. Additionally, the springs found in the bonus stages had received modifications to their color-palettes. Finally there were 2 enemies which only appeared once in the Master System version, the Burrobot and the Bomb. In the Game Gear version there are more Burrobots in Labyrinth zone, and the Bomb which was only encountered at act 2 of Sky Base is now infesting act 1 as well.