Sonic the Hedgehog (16-bit)

Sonic the Hedgehog is the debute game for the Sonic the Hedgehog series. It stars Sonic the Hedgehog as he travels across South Island to stop the villainous Dr. Eggman. The game is a 2D side-scrolling platformer as Sonic must traverse various environments laid with traps and hazards while collecting rings to sustain your life and breaking open Badniks along the way. The game incorporates speed as a gameplay element as Sonic can move various degrees of angles and use momentum in ways most platform games could not do at the time.

There are two versions of this game. One released for the Mega Drive/Genesis and the other for the Master System and Game Gear.

Mega Drive / Genesis
In the original 16-bit version, Sonic pursuits Dr. Eggman across South Island, passing these various zones:
 * Green Hill Zone
 * Marble Zone
 * Spring Yard Zone
 * Labyrinth Zone
 * Star Light Zone
 * Scrap Brain Zone

Each zone is divided into three acts, the last acts usually shorter and finishes with Dr. Eggman using modifications on his Egg Mobile for boss battles.

If Sonic completes any of the first two acts with 50 rings, a giant ring will appear near the goal post where he can enter the Special Stage where he will be able to obtain one of the six available Chaos Emeralds.

Master System & Game Gear
The story is exactly the same as the 16-bit verison other that Sonic taking a detour of zones and Dr. Eggman using different modifications for some of his boss battles.
 * Green Hill Zone
 * Bridge Zone
 * Jungle Zone
 * Labyrinth Zone
 * Scrap Brain Zone
 * Sky Base Zone

If Sonic completes any of the first two acts with 50 rings, he will be able to play a Special Stage where he will be able to obtain one of the six available Chaos Emeralds.