Special Stage (Sonic the Hedgehog 3 & Knuckles)

Special Stages in Sonic the Hedgehog 3, Sonic and Knuckles, and the locked-on version Sonic 3 and Knuckles, are a series of special levels. In these Special Stages, the player has to get the blue spheres and avoid the red spheres on checkerboard-designed arenas. These types of Special Stages are used as the core gameplay mechanic for the standalone game Blue Sphere.
 * For Special Stages in general, see here.

Like in the original Sonic the Hedgehog, the player has to find Giant Rings to enter the Special Stage. However Giant Rings are now hidden in every corner of the regular Zone, as mostly they can be found behind the walls on small holes or places, where only a certain playable character is able to get. The player is able to know this by recognizing the game's HUD go to a lighter palette. In the locked-on version of the game, multi-colored Giant Rings from Mushroom Hill Zone onwards can be found, which lead to the Emerald Altar of Hidden Palace Zone, where the player can enter the Special Stage, which will award the player with a Super Emerald. The player is able know the location of multicolored giant rings once the HUD starts to flash in multiple colors.

Gameplay
The opening line "Get Blue Spheres" sums up the goal. The player starts moving forward on large checkerboard arena with full of different objects, that are related to the player's goal. These Special Stages keep looping on, when the player reaches to north point and finds himself walking on the south point. To turn the moving direction to another, the player must press right or left on D-pad. As long as the player keeps going on the Special Stage for while, the moving speed starts to increase and keeps going on higher, making the navigating on the stage much more challenging. The player is also able to jump over small rows of bumpers, which can bounced the player backwards unless the player pushes up on D-pad to walk forward.

The player has to run through all Blue Spheres in all Special Stages. The left upper corner's HUD on the left corner shows the amount of Blue Spheres that are left, while the right upper corner's HUD shows how much rings are left. The player has to avoid Red Spheres all the time, even after the player has run through Blue Spheres, which turn to Red Spheres. Red Spheres transport the player out the Special Stage without getting Chaos Emerald. There are also yellow bumpers, which are only featured in Special Stages of Sonic & Knuckles, which can bounced the player for small distance, similar to Springs. The player is able to find rings on some of the sections of Special Stages on small groups, but for most of the time the player has to turn large groups of Blue Spheres into them. When the player runs on the perimeter of the Blue Sphere group, each of them turn to rings easily.

When the player gets 50 rings on the hand, he/she will get a continue and getting all rings from the Special Stage give a "perfect" bonus, which is equivalent of an extra life and worth of 50,000 points. When the player has collected all  the blue spheres from the Special Stage, all objects jump off the checkerboard arena and the player come across the Chaos Emerald, thus completing the Special Stage. By completing all seven Special Stages, Sonic is able to turn into Super Sonic, while also Sonic's ending is slightly different.

Super Emeralds
While in Sonic the Hedgehog 3, there are seven Special Stages for getting Chaos Emeralds, Sonic & Knuckles has another set of seven Special Stages as well. Special Stages in Sonic & Knuckles are mostly same looking, but much more challenging with more object layouts and more maneuvering routes to get Blue Spheres. However by completing these Special Stages, the player gets earned with Chaos Emeralds like at ones in Sonic the Hedgehog 3, thus Sonic and Knuckles being able to turn into Super Sonic and Super Knuckles in Sonic & Knuckles.

However in locked-on version of Sonic the Hedgehog 3 & Knuckles, the pattern is somewhat different. The player is able to get Chaos Emeralds in Sonic the Hedgehog 3 zones. When the player enters Mushroom Hill Zone, the player finds for the first time a rainbow-flashing Giant Ring at the hidden room. When the player transports to Emerald Altar of Hidden Palace Zone, Chaos Emeralds evoke large grey emeralds on their altars, that are Super Emeralds. By jumping on one of them will transport the character to a Special Stage of Sonic & Knuckles. At this time, the player will lose all Chaos Emeralds and is unable to turn into Super-form. However if the player doesn't have all of the Chaos Emeralds and is teleported into Hidden Palace (which happens only at that first Giant Ring), the player can only have one chance in turning one of the Chaos Emeralds into their respective Super Emeralds; the player has to get rest of Chaos Emeralds in order to evoke other Super Emeralds. The player can also ignore the multicolored Giant Ring and keep moving forward, as giant rings will then stay on their regular form and the playable character is able to keep his Super-form throughout the rest of the game.

By completing another seven Special Stages, all seven Super Emeralds have got their color scheme back and the player gets to play either as Hyper Sonic, Super Tails or Hyper Knuckles. The ending also changes drastically with some cases.

Trivia

 * In Sonic the Hedgehog 3, there is secret eighth Special Stage, where the player is able to enter by doing cheat code. The player must access the Level Select code and play the music number "07" on the Sound Test. After this the player must press A and Start button at the same time to enter the "Special Stage 1" section. By completing it, the player earn golden Chaos Emerald, which however doesn't have any effect to the game whatsoever.
 * In locked-on version Sonic 3 & Knuckles, there also exists the ninth Special Stage with yellow Super Emerald. To enter this Special Stage, the player must have enable Level Select and Debug Mode on while going to Sound Test section, the player must play the music number "07" and then go to the "Special Stage 1" while pressing A and Start button at same time.
 * The line "Get Blue Sphere" was originally called "Get Blue Balls" during game's development, which then got changed by game's testers in the final cut.