Sonic the Hedgehog 3 & Knuckles (also known as Sonic 3 & Knuckles or Sonic 3 Complete Version[2]) is a platform video game which is the result of locking-on Sonic & Knuckles with Sonic the Hedgehog 3 using the former catridge's unique "lock-on" technology. It is essentially a large combined game of its two lock-on components which contains all Zones from the said games and also contains special features unique to this game. Sonic the Hedgehog 3 & Knuckles is the original Sonic the Hedgehog 3 the developers intended to release but time constraints by Sega resulted in this game being split into two.[3]



While the gameplay in Sonic 3 & Knuckles generally remains identical to its two components, there are new features exclusive in this game and there are a large number of gameplay changes present.


In Sonic 3 & Knuckles, the Zones of both Sonic the Hedgehog 3 and Sonic & Knuckles are placed together, featuring a total of 14 Zones.

  1. Angel Island Zone
  2. Hydrocity Zone
  3. Marble Garden Zone
  4. Carnival Night Zone
  5. IceCap Zone
  6. Launch Base Zone
  7. Mushroom Hill Zone
  8. Flying Battery Zone
  9. Sandopolis Zone
  10. Lava Reef Zone
  11. Hidden Palace Zone
  12. Sky Sanctuary Zone
  13. Death Egg Zone
  14. The Doomsday Zone

Competition Zones

In Competition Mode, there are five Zones:

  1. Azure Lake Zone
  2. Balloon Park Zone
  3. Chrome Gadget Zone
  4. Desert Palace Zone
  5. Endless Mine Zone

New features

Super Emeralds

Main article: Super Emerald

The Master Emerald (center-top) surrounded by the seven Super Emeralds.

Super Emeralds are enhanced versions of the Chaos Emeralds. When the player enters their first Special Stage in Mushroom Hill Zone, they teleport to Hidden Palace Zone where the Chaos Emeralds are taken from them and transformed into gray (apparently depleted of power) Super Emeralds, thus beginning the Super Emerald quest. If the player does not have all of the Chaos Emeralds prior to reaching Mushroom Hill Zone, the acquired Chaos Emeralds will become Super Emeralds and the player is given the opportunity to acquire the first Super Emerald. However, the player will not be allowed to return to Hidden Palace Zone via the Giant Rings until they collect the remaining Chaos Emeralds. If the player has not collected a single Chaos Emerald by Mushroom Hill Zone and goes to Hidden Palace Zone via the first Giant Ring, the player must exit the area by jumping on the teleporter in the bottom central part of the room, directly below the Master Emerald.

Super/Hyper transformations

By collecting all seven Super Emeralds from the Special Stages, each of the three main playable characters (Sonic the Hedgehog, Miles "Tails" Prower and Knuckles the Echidna) will have access to more powerful forms upon summoning the power of the Emeralds. As with super transformations, the player must have collected fifty Rings and then press the jump button during a jump (as long as Sonic is not equipped with an elemental shield) to initiate the transformation. While under the transformation, one Ring is consumed per second and once the player has zero Rings, completes the Act or enters a Bonus Stage at a Star Post, the user will revert back to normal.

Name Image Description
Hyper Sonic Hyper sonic.gif Enhanced version of Super Sonic. While retaining all of Super Sonic's traits, including increased running speed, high jumping ability, the ability to smash through patterned walls (except for those that are intended only for Knuckles to break through) and invulnerability to enemy attacks and obstacles, Hyper Sonic's movements have been increased further, he has the ability to breathe underwater, and he gains a new ability (called the "Hyper Flash") which serves as a mid-air dash towards any direction and can also destroy all on-screen enemies at once.
Super Tails Super-Tails-Gif-2.gif Tails' super transformation. Following the regular traits of a super form, Tails' running speed, jumping height and flying speed are all increased and he is also invulnerable to enemy attacks and obstacles. In addition, Tails is aided by four "Super" Flickies who will automatically attack nearby enemies, including bosses, acting as bodyguards for him.
Hyper Knuckles Hyper Knuckles animated.gif Enhanced version of Super Knuckles. While retaining all of Super Knuckles' traits, including increased running speed, increased gliding speed, increased wall-climbing speed and invulnerability to enemy attacks and obstacles, Hyper Knuckles' movements have been increased further, he has the ability to breathe underwater, and he gains a new ability (called the "Gliding Shock Wave Attack") where whenever Knuckles glides into a wall at sufficient speeds, the impact will create a sudden tremor that destroys all on-screen enemies at once.


  • The player can play as Knuckles in the Sonic the Hedgehog 3 levels, although Knuckles' opening cutscene from Sonic & Knuckles has been removed in favor for transiting from Launch Base to Mushroom Hill.
    • As such, Knuckles' level layouts are different from Sonic's and Tails' in most cases, with new areas and bosses that are generally more challenging than Sonic/Tails' bosses.
  • Knuckles does not face a boss at Carnival Night Zone Act 2 and simply has to jump on the Capsule switch to clear the Act.
    • It is still possible for Knuckles to fight the boss (piloted by EggRobo) that Sonic and/or Tails normally fight in their version. The transition from Carnival Night Zone to IceCap Zone with Knuckles still remains the same as with Sonic and/or Tails when he hops in the cannon, but when IceCap Zone starts, Knuckles will still be seen emerging from the teleporter instead as if he cleared the previous Zone normally.
  • The player can play as Tails in the Sonic & Knuckles levels (except for The Doomsday Zone) or have Tails follow Sonic throughout the entire game.
  • After the levels of Sonic the Hedgehog 3 are finished, the screen scrolls downward with the Death Egg falling rather than playing the normal ending animation and gameplay immediately proceeds to the levels of Sonic & Knuckles.
    • The Big Arm boss fight at Launch Base Zone Act 2 is omitted for Sonic and Tails.
    • Knuckles will still have to fight the Big Arm but to even things out, the Ball Shooter boss fight is omitted for him.
  • Game progress can be saved in all levels (including those from Sonic & Knuckles) using the save feature from Sonic the Hedgehog 3.
    • The number of save files has been increased from six to eight.
    • Upon accessing 1 Player Mode for the first time, any existing save files from Sonic the Hedgehog 3 will be imported to Sonic the Hedgehog 3 & Knuckles. Save files imported from Sonic the Hedgehog 3 will retain the character, last zone (a completed save file in Sonic the Hedgehog 3 will become a Mushroom Hill Zone save file) and number of Emeralds, but will default to three lives and zero continues. This feature is missing in some later compilations.
    • Save files now display information about the number of continues, lives and the Chaos Emeralds surround the player's character as the player collects them (the Chaos Emeralds are replaced with their correspondingly colored Super Emeralds when the player collects them).
  • The BGM tracks that were different between Sonic the Hedgehog 3 and Sonic & Knuckles use only the Sonic & Knuckles version. These include the title screen, 1-Up, Invincibility, Act 1 boss, Knuckles' theme, and end credits. As seen in the November 3, 1993 prototype, the Act 1 boss music that appears in Sonic & Knuckles is the music originally intended for all Act 1 bosses throughout the entirety of Sonic the Hedgehog 3.
  • All Act title cards now display the game title of Sonic 3 & Knuckles.
  • Passing a Star Post can now open up all three Bonus Stages, including the slot machine stage (20-34 rings required), the magnetic orbs stage (35–49 rings required) from Sonic & Knuckles as well as the gumball machine (50–65 rings required) from Sonic the Hedgehog 3.
  • There are slight differences in object and enemy placement in some of the Sonic 3 Zones as well (Launch Base Zone in particular).
  • The method of accessing Sound Test/Act Select and Debug Mode is different (see Cheats).
  • With Debug Mode enabled, the player can access any level with any character, even those that cannot be normally accessed (such as Sonic and/or Tails in Knuckles' Sky Sanctuary Zone and vice-versa, or Tails or Knuckles in The Doomsday Zone).
  • There are a total of nine different endings; each character (Sonic and Tails together have the same as Sonic alone.) has one with zero to six Chaos Emeralds, one with all seven Chaos Emeralds and zero to six Super Emeralds, and the third with all fourteen Chaos and Super Emeralds.


  • Sound Test/Act Select: At Angel Island Zone, grab hold on a swinging rope and press the following in order: Left, Left, Left, Right, Right, Right, Up, Up, Up. (A Ring chime will sound if successful.) Then pause the game and press A Button (Sega Genesis).svg to return to the title screen. The Sound Test option should be available to select below "Competition".
  • Debug Mode: After accessing the Sound Test, play through either act of Mushroom Hill Zone and grab a hold on one of the manual elevators and press the following in order: Left, Left, Left, Right, Right, Right, Up, Up, Up. (A Ring chime will sound if successful.) Then pause the game and press A Button (Sega Genesis).svg to return to the title screen. Go to the Sound Test again then while highlighting any Act hold A Button (Sega Genesis).svg before selecting the Act to start the Act with Debug Mode.


Scrapped mobile re-release

On October 18, 2014 (the twentieth anniversary of the original release of Sonic & Knuckles and subsequently Sonic the Hedgehog 3 & Knuckles), Christian Whitehead and Simon Thomley (who developed the remastered versions of Sonic the Hedgehog CD, Sonic the Hedgehog and Sonic the Hedgehog 2) released a concept video showcasing a prototype of a remastered version of Sonic the Hedgehog 3 for smartphone devices they have worked on for a while (see video below). However, circumstances prevented the development from proceeding any further.[4]

As showcased in the video, the following aspects of the game were completed:[4][5]

  • The title screen
  • Angel Island Zone with all enemies, gimmicks, bosses and intro/intermission sequences
  • All three Bonus Stages
  • Special Stages, including “Blue Sphere” functionality


Sonic the Hedgehog 3 & Knuckles received critical acclaim, with many fans still regarding it as the best Sonic the Hedgehog game of the franchise.[citation needed]


  • If using Debug Mode and a certain number of S Monitors are destroyed at once (most effectively with the Insta-Shield), then the controls of the character will be locked and by pressing Start the game will turn back into Sonic & Knuckles. This is the only way to access Debug Mode in Sonic & Knuckles.
  • Taking care to avoid as many Special Stages as possible, it is possible to finish the game with only the seven Chaos Emeralds, retaining their Super powers until the very end of the game. In this case, the game endings will resemble the good endings from Sonic & Knuckles.
  • In the game's level select menu, there is a sound test menu. Interestingly, setting the sound test to 26 will cause the Sonic the Hedgehog 3 credits music to play, despite it not being used anywhere in Sonic 3 & Knuckles. Interestingly, the other tracks that differ between Sonic 3 and Sonic & Knuckles (1-Up, Invincibility, Knuckles' theme, Act 1 boss, Intro) use the Sonic & Knuckles version.
  • The "& Knuckles" part of the title spawned into a popular Internet meme in modern times.[6]



See also


  1. 1.0 1.1 In this platform, Sonic the Hedgehog 3 & Knuckles is available if Sonic the Hedgehog 3 and Sonic & Knuckles are downloaded on the same account.


  1. Sonic 3 & Knuckles on Steam. Valve. Retrieved on 26 January 2015.
  2. Sonic Mega Collection (Plus) game description
  3. Sega's Yuji Naka Talks!. GameSpy. Retrieved on 31 December 2014. “Sonic 3 is literally half a game. Sega management back then wanted the game out at a certain time and we only had half the stages done, so we had to put the leftovers into Sonic and Knuckles. So when you bought S&K and attached it to Sonic 3, you got the whole of what Sonic 3 was planned to have been.”
  4. 4.0 4.1 Chris Mawson (2 April 2015). Sonic the Hedgehog 3 Remastered Interview with Christian 'The Taxman' Whitehead. Power Up Gaming. Retrieved on 19 April 2017.
  5. Stealth (18 October 2014). Sonic 3 (& Knuckles) 20th Anniversary. Tumblr. Retrieved on 29 March 2015.
  6. & Knuckles. Know Your Meme (21 August 2010).
Sonic the Hedgehog 3 & Knuckles

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