Video Game / Blue Sphere

The Sonic & Knuckles cartridge is designed to Lock-On with a Sonic 3 or a Sonic 2 cartridge. It will not work with non-Sonic cartridges.
— The misleading disclaimer in the Sonic & Knuckles instruction manual.

Blue Sphere is a hidden minigame included on the Sonic & Knuckles cartridge, based on the Special Stages of Sonic 3 & Knuckles. It is playable when you place (almost) any Genesis cartridge other than Sonic the Hedgehog 2 or 3 into S&K's lock-on slot and press the A, B, and C buttons at the same time. The vast majority of Genesis cartridges you can do this with only give you a single stage. note  If, however, you do this with the first Sonic game or Sonic Classics 3 in 1, you'll have access to a whopping 134,217,728 stages. note 

Upon completion of the stage, you'll be given a twelve-digit password for use when you play the game with the original Sonic the Hedgehog or the aforementioned compilation re-release locked into the top slot of S3&K. It also appears as its own game option in Sonic Mega Collection, Sonic Mega Collection Plus (which gave the minigame an official name for the first time), and the Sonic and Knuckles Collection for the PC.

Not to be confused with Star Ocean: Blue Sphere.

This game provides examples of:

  • Cast Speciation: Averted. You can play as Sonic or Knuckles, but there's no difference. All you can do is run and jump, and the speed you move at and your jump height is out of your control.
  • Difficulty by Acceleration: You move faster the longer you take to complete the stage.
  • Dungeon Bypass: Getting every ring in a stage in the full version of the game to get a "Perfect" skips you 10 stages ahead.
  • Easter Egg: The game's actual existence outside of Sonic 3 & Knuckles. Technical difficulties with the palette prevented Sonic Team from doing Knuckles in Sonic 1, so they put this game in. The game's existence and the button combination required to play it weren't mentioned in the manual, which in fact said not to put in any other game.
  • Endless Game: After a while, certain levels repeat themselves and eventually just carries on from Level 1 again. Only if you put in the specific cartridge needed to play the full game, though.
  • Exact Words: The Sonic & Knuckles manual states that the game's lock-on technology won't work with non-Sonic games. While it clearly states that you're only supposed to use Sonic 2 or 3 with it, the manual doesn't rule out using Sonic 1 or Sonic Classics 3 in 1 as well.
  • Nintendo Hard: Some of the combinations are devilish, especially when running for perfects.
  • No Name Given: The original minigame was never given a title. Sonic Mega Collection was what gave it the title that it is known as today.
  • No Plot? No Problem!: Just press the buttons and go right in.
  • One-Hit-Point Wonder: If you touch a red sphere, you instantly lose.
  • Password Save: There are two kinds of passwords. One for the stage as presented in the main game, and one for the version of the stage where a non Sonic 1 or Sonic Classics 3 in 1 cartridge was used. The former allows you to advance the game, whereas you're stuck with the password's level with latter.
  • Puzzle Game: Collect the blue spheres and rings while avoiding the red spheres.
  • Spell My Name with an "S": Some sources list this game as Blue Spheres.
  • Suspiciously Specific Denial: The manual says that putting any game other than the second or third Sonic game won't work. You do it anyway. And then you press all the buttons for no reason. This is further emphasized with the opening screen of Blue Sphere saying "NO WAY! NO WAY! NO WAY! NO WAY?" Notice the question mark.
  • Video Game Geography: Topologically, the levels are toroids. Visually, they're spheres. The disconnect can be disorienting, if you notice it while playing.