Blue Sphere
From Sonic Retro
Blue Sphere is the game created by locking on Sonic & Knuckles to Sonic the Hedgehog. It is a compilation of 128,016,000 "Special Stages" in the same style (and engine) of the ones featured in Sonic the Hedgehog 3 and Sonic & Knuckles, but there is a total of 134,217,728 levels in all. However, after level 128,016,000, some of the previous levels begin to reappear. After completing all 134,217,728 (227) stages, it restarts from the beginning.
The levels in Blue Sphere are slightly different than the special stages in Sonic the Hedgehog 3 and Sonic and Knuckles. In Blue Sphere, the ring counter decreases rather than increases, and if you collect all the rings and blue spheres in a level, you receive a "perfect" score and are presented a screen showing the stage's difficulty. Then you are advanced 10 levels.
The "No Way? No Way!" message that scrolls across the screen at first seems to inform the player that the game attached is not Sonic the Hedgehog 2 or 3. Pressing the A, B, and C buttons simultaneously brings up the main screen on Blue Sphere. When at the main screen, pressing A, B, or C allows you to switch characters. However, you cannot play as Tails or Sonic with Tails following like in Sonic 3 and Knuckles.
Each time you complete a stage, you are given a 12-number password for the stage. Also, each stage has a difficulty level assigned to it, represented by an icon. There are 13 difficulty levels in all. Difficulty is assigned based on the number of spheres in each region of the stage's map, so some level 13 stages might actually be less difficult than level 12 or 11.
List of icons by difficulty level (Note: Each difficulty level contains the icon of all difficulty levels below it)
- Nothing
- Sonic
- Tails
- Knuckles
- Robotnik
- Mecha Sonic
- Eggrobo (flying)
- Chickens
- Squirrels
- Rabbits
- Master Emerald
- Sonic & Knuckles logo
- Sonic turns into Super Sonic
Blue Sphere can also be created by locking on Sonic & Knuckles to any other Sega Mega Drive game, producing one of the stages featured in the Sonic the Hedgehog Blue Sphere, based on something in the header of the game.
Please note, however, that playing these levels via a game with battery back up will erase saved games. Also note that this won't work with games made after Sonic & Knuckles was released. There are also some instances of it not working with games made before Sonic & Knuckles, such as Phantasy Star IV.
The name Blue Sphere comes from the name shown in its listing in Sonic Mega Collection.