Sonic the Hedgehog 2 (8-bit)

The first Game Gear Sonic sequel, from 1992. Set on South Island."'Robotnik returns!""All was peaceful and quiet on South Island after Sonic the Hedgehog crushed the plans of the diabolical Dr. Ivo Robotnik for the first time. Far too quiet, in fact, for a hyper young hedgehog who craves action. So Sonic left South Island in search of other adventures.""When he returned, Sonic found no sign of his friends anywhere. Confused, he went back to his digs to think, and found a note waiting for him. It was from Miles (or 'Tails' as he is called), a two-tailed fox who is one of Sonic's closest friends:""Dear Sonic:""'Robotnik is back, and he's captured all of the animals on the island! He is hiding me in a place called the Crystal Egg. In order to free me, you have to find and bring the six Chaos Emeralds.""'Robotnik made me write this. He says he's waiting for you, and he's created six really nasty robots in order to 'get rid of you once and for all.' I don't know what he has planned, but Sonic, please be careful!""Sincerely, Tails'""There was no time to waste! The letter fluttered to the floor as Sonic dashed off to find the Chaos Emeralds and save his friends.' - — Sonic the Hedgehog 2 (8-bit) English instruction manual"

Levels

 * Under Ground Zone
 * Sky High Zone
 * Aqua Lake Zone
 * Green Hills Zone
 * Gimmick Mountain Zone
 * Scrambled Egg Zone
 * Crystal Egg Zone