Mega Drive / Genesis1994Sonic TeamLock-On

Sonic & Knuckles (1994)

The second half of the Sonic 3 saga, on a cartridge with a slot on top: Knuckles finally gets to play, the Master Emerald takes centre stage, and the Death Egg rises one last time.

Released18 October 1994 (US/EU) · 28 October 1994 (JP)

DeveloperSonic Team at Sega Technical Institute

PlayableSonic or Knuckles

ZonesSeven, plus The Doomsday Zone

Lock-OnSonic 3, Sonic 2, Sonic 1

MusicHoward Drossin and the Sega Sound Team

Overview

Sonic & Knuckles features unique Lock-On Technology, introduced when it was released on the Genesis / Mega Drive.

For many fans this is where the classic era ends. It was the last Sonic game directed by Hirokazu Yasuhara and the last to come out of Sega Technical Institute, and it closes the story that began with the Death Egg in Sonic 2: the station has crashed into Angel Island’s volcano, Sonic stumbles on the Master Emerald that once held the island up, and Knuckles finally works out who has been lying to him.

It is also the second half of Sonic 3, sold on a cartridge with a slot in the top. On its own you get seven new zones, playable as Sonic or, at last, as Knuckles, who can glide, climb and punch through walls. Put Sonic 3 in the slot and the two become Sonic 3 & Knuckles: fourteen zones, Tails back in the line-up and a set of Super Emeralds to hunt.

Quick Answers

The essentials, with links to the detail.

Plot / Story

At the heart of Angel Island sits the Master Emerald, a gem bigger than any Chaos Emerald and bound up with their power. It is the reason the island ever floated, and guarding it is the whole of Knuckles’ life. Sonic does not know it exists until the start of this game.

He finds it by following Knuckles. Tails has flown Sonic down into Mushroom Hill, a forest of giant mushrooms, and from there Sonic watches the echidna slip through a hidden door. Inside, a huge glowing ring draws him in, and the flash that follows drops him in a chamber with an ornate altar: seven empty places arranged round an enormous emerald. In Sonic 3 & Knuckles, any Chaos Emeralds he is carrying are pulled to it and replaced by seven larger stones, the Super Emeralds, which then have to be restored.

Above it all, the Death Egg is not finished. Sonic and Tails stopped Eggman’s rushed relaunch at the end of Sonic 3, but the station came down on top of the island’s volcano with its great Eggman face staring inland, and the doctor now needs a power source big enough to lift it again.

Sonic’s story

Sonic boards Eggman’s airship, the Flying Battery, digs through the quicksand and pyramid of Sandopolis and goes deep into the volcano at Lava Reef. In Hidden Palace, Knuckles’ sanctuary, the two finally fight, and as they do the Death Egg rises out of the volcano. Eggman swoops in, snatches the Master Emerald with a claw on his Egg Mobile and shocks Knuckles when he tries to stop him.

Knuckles has seen enough. He opens the way to Sky Sanctuary, sacred ruins in the sky that only he is allowed to visit, where Eggrobos pour out of the climbing Death Egg and Mecha Sonic, rebuilt and riding the Egg Mobile, tries Eggman’s old tricks. Beaten but not destroyed, it is left behind as the ruins crumble, and Sonic leaps on to the Death Egg for the final assault. With all seven Chaos Emeralds he goes one step further, transforming to chase Eggman through an asteroid field in The Doomsday Zone and win back the Master Emerald.

Knuckles’ story

Pick Knuckles on the title screen and a short scene sets his story after Sonic’s. One Eggrobo has survived the wreckage, and it spends the game hounding the guardian, flying Eggman’s boss machines in his place.

Knuckles’ route is harder and shorter: his game ends in Sky Sanctuary, where the Eggrobo carries him off to the last boss. Mecha Sonic was not finished off after all and has taken the Master Emerald, and its destruction brings the last of the ruins down. Knuckles’ good ending shows Angel Island floating high in the sky once more. In Sonic 3 & Knuckles the Eggrobo turns out to have been working for Mecha Sonic, which destroys it by accident.

Emeralds, bonus stages and super forms

Giant rings hidden in the acts still lead to the Blue Sphere Special Stages, but only up to Lava Reef, the last zone that has them. All seven Chaos Emeralds unlock the good ending and the super forms, now Super Sonic and Super Knuckles: collect 50 rings and press jump twice. Pass a Star Post with 20 to 34 rings for a rotating slot-machine maze in the style of Sonic 1’s Special Stage, or with 35 or more for a room of glowing spheres that pull the character in.

In the combined game the Chaos Emeralds become Super Emeralds, restored through a second round of Special Stages at the Master Emerald’s altar, and with all seven Sonic can become Hyper Sonic.

Zones in Sonic & Knuckles

Seven zones, plus The Doomsday Zone for Sonic. In Sonic 3 & Knuckles these become zones 7 to 14, after Sonic 3’s six.

1. 
   Mushroom Hill ZoneTwo actsA forest of giant mushrooms, and the first stage of Knuckles’ first full adventure (he had only been playable in Sonic 3’s Competition mode). Butterdroid, Cluckoid, Dragonfly, Madmole and Mushmeanie.
2. 
   Flying Battery ZoneTwo actsOn board Eggman’s airship, caught as it passes over Mushroom Hill; electromagnets, capsules and a sub-boss disguised as one. Blaster and Technosqueek.
3. 
   Sandopolis ZoneTwo actsQuicksand and stone blocks outside, then a pyramid full of ghosts. Skorp, Sandworm, Rock’n and the ghostly Hyudoro.
4. 
   Lava Reef ZoneTwo actsInside Angel Island’s volcano, and the last zone with giant rings. Iwamodoki, Fireworm and Toxomister.
5. 
   Hidden Palace ZoneShortThe shrine of the Master Emerald, where Sonic and Knuckles fight; a pass-through for Knuckles.
6. 
   Sky Sanctuary ZoneOne act eachFloating ruins above Angel Island, forbidden to all but Knuckles. Eggrobos and Mecha Sonic.
7. 
   Death Egg ZoneSonic and Tails onlyInside the Death Egg itself, for Sonic and Tails. Spikebonker and Chainspike.
8. 
   The Doomsday ZoneOne actSonic only, with seven Emeralds: a super-powered chase through space to recover the Master Emerald.

In comics, TV & other media

The comics treated Sonic & Knuckles very differently. More in Sonic in other movies and media.

Characters

A two-hero game, with Eggman’s robots taking turns as the villain.

Character	Who they are	In this game	Stats & abilities
Knuckles the EchidnaPlayable in a main story for the first time	The guardian of Angel Island and its Master Emerald, last of the echidnas. Tricked by Eggman in Sonic 3, he finally sees the truth when Eggman steals the Master Emerald in front of him.	Fights Sonic in Hidden Palace, then helps him on to Sky Sanctuary. In his own story he is chased by an Eggrobo and ends up facing Mecha Sonic for the Master Emerald.	Glides (press jump again in mid-air) Climbs walls he glides into Smashes blocks just by running into them Jumps lower than Sonic Super Knuckles with seven Emeralds
Sonic the HedgehogThe hero	Still on Angel Island after Sonic 3, determined to finish off the Death Egg for good.	Follows Knuckles to the Master Emerald, battles through seven zones to the Death Egg and, with every Emerald, into space for the final fight.	Insta-Shield, Spin Dash and shield moves as in Sonic 3 Super Sonic with seven Emeralds Hyper Sonic with all Super Emeralds (Sonic 3 & Knuckles)
Dr. EggmanDr. Robotnik in the West	With the Death Egg stuck in a volcano, he sets his sights on the Master Emerald, the one power source big enough to get it back into space.	Steals the Master Emerald in Hidden Palace and launches the Death Egg. Sonic’s final opponent, in the Death Egg and then in space.	Flies the Egg Mobile with a giant claw Boss machines throughout Sonic’s story
EggroboDebut	A round robot with a laser gun, built in Eggman’s image. Swarms of them launch from the Death Egg in Sky Sanctuary.	One survivor becomes Knuckles’ nemesis, piloting the boss machines in his story, until it is revealed to be serving Mecha Sonic.	Fires a laser pistol Later playable in Sonic R, as Eggmanrobo
Mecha SonicRebuilt and upgraded	The robot double from Sonic 2, rebuilt and upgraded on Angel Island.	Rides the Egg Mobile against Sonic in Sky Sanctuary and survives the fight. In Knuckles’ story it returns, now in possession of the Master Emerald, as his last boss.	Uses Eggman’s old boss tricks Picture: Sega’s concept art for the original Mecha Sonic in Sonic 2
Super Sonic & Super KnucklesSuper forms	Sonic’s golden form returns, and for the first time another character gets one: Super Knuckles.	Earned by winning all seven Chaos Emeralds in the Special Stages, which can only be found up to Lava Reef Zone. Super Sonic is the key to The Doomsday Zone.	50 rings, then press jump twice Hyper Sonic with all seven Super Emeralds (Sonic 3 & Knuckles)
The BadniksEggman’s army	A new set of robots for the second half of the island.	Seventeen kinds across the zones, listed below.	Break them to free the animals inside.

The Badniks

Every Badnik in Sonic & Knuckles and where it lives. Most pictures are Sega’s own artwork from Sonic Scene’s gallery; the rest are game sprites.

• ButterdroidMushroom HillA butterfly, usually in pairs.
• CluckoidMushroom HillA rooster on a weather vane that blows you back with a gust of wind.
• DragonflyMushroom HillBobs up and down; only its head can be attacked.
• MadmoleMushroom HillA mole that pops out of its hole and throws mushrooms.
• MushmeanieMushroom HillHides among real mushrooms, then bounces after you.
• BlasterFlying BatteryFires small shots.
• TechnosqueekFlying BatteryA robot mouse that runs along walls, floors and ceilings.
• SkorpSandopolisA scorpion that whips out its sting.
• SandwormSandopolisA Caterkiller-like worm that burrows through the quicksand.
• Rock’nSandopolisA robot guarded by sand blocks.
• HyudoroSandopolisNot a Badnik but the ghosts that haunt the pyramid.
• IwamodokiLava ReefDisguised as a rock, it blows itself up.
• FirewormLava ReefA caterpillar with fire on its back and spikes underneath.
• ToxomisterLava ReefA smokestack that puffs out poison clouds.
• EggroboSky SanctuaryEggman-shaped robot with a laser pistol.
• SpikebonkerDeath EggCircled by a big spiked ball.
• ChainspikeDeath EggA blue robot that shoots spikes out in four directions.

The people who made it

The Sonic 3 team, credited again. Names and roles from the game’s credits.

How it was made

Sonic & Knuckles is the back half of a game that would not fit: what was cut from Sonic 3, how the halves were joined, and how Sega sold the result.

Finishing what Sonic 3 started

The team behind Sonic 3 wanted to swing for the fences, Takashi Iizuka later said, with bigger stages that simply took longer to build. No cartridge of the time could hold everything, and Sega wanted Sonic 3 in American shops in time for a McDonald’s promotion, so the game was cut in two. Sonic 3 went out in early 1994, not quite finished, and the rest was completed as a second cartridge. Mushroom Hill, which now had to work as an opening stage, was made easier to suit.

Players could see the seams. Knuckles leaves Sonic 3 after a wobbly girder knocks him over, some stages hint at paths Sonic and Tails cannot reach, and the level select names three zones that cannot be played: Flying Battery, Mushroom Valley and Sandopolis. A fuller single cartridge, “Sonic the Hedgehog 3 Limited Edition” or “Sonic 3+”, was rumoured at 24 megabits, but once the split was settled the effort went into a second part that could plug into the first.

Lock-On Technology

Joining the halves needed new hardware, so the team took the problem to Sega’s hardware division, which supplied the lock-on adapter built into the cartridge. Roger Hector, who ran STI, said the idea of one cartridge plugging into another went back to the gap between Sonic 1 and Sonic 2. Players were bound to try other games in the slot, so there are rewards for those too:

• Sonic the Hedgehog: Blue Sphere, a puzzle game built from a huge number of Special Stage layouts, with a sixteen-digit password so you can come back later.
• Sonic the Hedgehog 2: Knuckles in Sonic 2, the 1992 game played from start to finish as Knuckles, tweaked to suit his moves.
• Sonic the Hedgehog 3: Sonic 3 & Knuckles, both halves as one game with all three heroes playable throughout.

Knuckles was given Sonic 2 because his moves suited its levels; the designers tried the same with Sonic 1 and decided its layouts did not work for him. Sega sold the slot as a bonus for older games, but Sonic 3 had been planned around it from the start: its code already holds pointers to the level changes made when the two are joined.

Alcatraz and “Rock the Rock”

Sega spent heavily. Sonic & Knuckles had a $45 million marketing campaign at a time when around $5 million was usual for a game, and it reached shops in the same season as Nintendo’s Donkey Kong Country, each side selling a new technical trick: Lock-On against pre-rendered 3D graphics.

The showpiece was a tournament backed by Blockbuster Video and MTV. Qualifiers around the world, sixteen of them at Hard Rock Cafes in the US, produced fifty contestants, who were flown to San Francisco in handcuffs and prison uniforms for a final on Alcatraz on 8 October, presented by Bill Bellamy and Daisy Fuentes. Everyone chased rings in Mushroom Hill; the last two, Chris Tang, 18, of San Francisco and Mark Guinane of Boston, then played Launch Base as Knuckles. Tang won by 30 rings, taking $25,000 and the title “World’s Most Hard-Core Gamer”.

Very little had been shown beforehand. Sega’s Gamer’s Day in June revealed only a logo and the release date, 18 October; the full unveiling was MTV’s Rock the Rock special, also billed as Inside Sonic & Knuckles, broadcast on 17 October, the day before launch.

Firsts: what this game introduced

Sonic & Knuckles added more than its slot:

Cheats & secrets

Some of Sonic & Knuckles’ best secrets need a second cartridge.

Level Select

In Mushroom Hill Zone, grab one of the pulleys and press Left, Left, Left, Right, Right, Right, Up, Up, Up. A ring sound confirms it. Pause, press A to return to the title screen, then press A and Start for the level select. (Sonic 3’s zones are listed but only load with Sonic 3 locked on; otherwise they start Mushroom Hill.)

Debug Mode

There is no simple code on its own. Debug mode can be reached only through a convoluted trick that starts in Sonic 3 & Knuckles and deliberately crashes the game.

Knuckles takes a bow

In Sky Sanctuary, after Knuckles has opened the bridge for Sonic, stand in the right spot and duck. Knuckles turns and waves you on your way.

Lock-On games

Put Sonic 3 in the top slot for Sonic 3 & Knuckles, Sonic 2 for Knuckles in Sonic 2, or Sonic 1 for Blue Sphere.

Checked against Sonic Retro’s hidden content page, November 2026.

Glitches, exploits and oddities

Mostly small, mostly about Knuckles, who was added to a game built around Sonic.

Eggman instead of Eggrobo

In Knuckles’ story the bosses should be flown by the Eggrobo. In Flying Battery Act 2 it is always Eggman, because the artists never drew the Eggrobo for that boss’s head-on view; fixed in Sonic Origins. In Mushroom Hill Act 2, after losing a life, Eggman’s face can also appear instead of the Eggrobo’s; fixed in the Sonic & Knuckles Collection and Sonic Origins.

Off-colour monitors

Monitors borrow their blues from Sonic’s palette, so when playing as Knuckles some, such as the Water Shield, show the wrong colours. Never fixed, even though Knuckles in Sonic 2 has code to correct it.

Safe spikes in Sandopolis

Stand on one of Sandopolis’s moving spiked pillars while invincible and you stay unhurt after the invincibility runs out, unless you jump back on to the spikes.

Vertical wrap

The Sonic 3 trick of ducking and jumping in a looping act also works in Sandopolis Act 2 and Sky Sanctuary, letting you slip through objects. Fixed in Sonic Origins.

Videos & media

Two official trailers for the collection where Sonic & Knuckles lives today, as part of Sonic 3 & Knuckles.

SEGA’s official reveal trailer for Sonic Origins (2022).

The announcement trailer for Sonic Origins Plus (2023), which added Amy Rose as a playable character in Sonic 3 & Knuckles, from the official Sonic the Hedgehog channel.

Trivia & facts

• Sky Sanctuary’s internal name was “Castle in the Sky”, a nod to the 1986 Hayao Miyazaki film.

• 

  Eggrobo later turned up as a playable racer in Sonic R, as “Eggmanrobo”.
• Hidden Palace Zone shares its name with a famous cut zone from Sonic 2, but is an unrelated level. The stage select lists it as Lava Reef Act 4, because it sits in a slot reserved for Lava Reef.
• The mural behind Sonic’s fight with Knuckles in Hidden Palace appears to foretell the final battle of The Doomsday Zone.
• Flying Battery Zone was originally meant for Sonic 3, between Carnival Night and IceCap.
• Knuckles’ story never visits Death Egg Zone, and he is not normally playable there.
• Both Alcatraz finalists, winner Chris Tang and runner-up Mark Guinane, were promised a year’s worth of Sega releases.

Media & artwork

Box art, artwork and screenshots, mostly from Sonic Scene’s own galleries. Select any image to view it larger.

• Box art from Sonic & Knuckles
• Screenshots from Sonic & Knuckles
• Official artwork from Sonic & Knuckles

Legacy

Sonic 3 & Knuckles is still the version almost everyone plays, and the yardstick for 2D Sonic.

From Mega Drive to Sonic Origins

• Mega Drive / Genesis 18 October 1994 – North America, Europe and Australia; Japan on 28 October.
• Sonic & Knuckles Collection 1997 – Windows PC: Japan 14 February, North America 14 March, Europe 20 March.
• Sonic Jam 1997 – Sega Saturn.
• Sonic Mega Collection 2002 – GameCube, then PlayStation 2 and Xbox.
• Xbox Live Arcade 9 September 2009 – Xbox 360.
• Virtual Console 2009–2010 – Wii: Japan 27 October 2009, Europe 12 February 2010, North America 15 February 2010.
• Sonic Origins 23 June 2022 – As Sonic 3 & Knuckles; Sonic Origins Plus (2023) added Amy.

Also playable in

From our original page:

• 1997 Sonic & Knuckles Collection, PC
• 1997 Sonic Jam, Sega Saturn
• 1999 Sonic & Garfield Pack, PC
• 2000 Sonic Action Pack, PC
• 2001 Sonic Action 4 Pack, PC
• 2002 Twin Pack (Sonic & Knuckles Collection with Sonic CD), PC
• 2002 Sonic Mega Collection, Nintendo GameCube
• 2003 Sega PC Mega Pack, PC
• 2004 Sonic Mega Collection Plus, PlayStation 2 and Xbox
• 2005 Super Monkey Ball Deluxe with Sonic Mega Collection Plus, Xbox double pack
• 2008 Blaze’s Dual Game Controller Player (a plug-and-play system)
• 2009 Sega Fun Pack (Shadow the Hedgehog with Sonic Mega Collection Plus), PlayStation 2
• 2009 Sonic’s Ultimate Genesis Collection, PlayStation 3 and Xbox 360
• 2009 Blaze’s Sega Mega Drive (a plug-and-play system)
• 2009 Sonic & Knuckles on Xbox Live Arcade
• 2009 Sonic PC Collection, PC
• 2010 Sonic Classic Collection, Nintendo DS
• 2010 Virtual Console, Nintendo Wii

Since then: Sonic Origins (2022). Checked against Sonic Retro, November 2026.

Where to play it today

Sonic Origins on PlayStation, Xbox, Nintendo Switch and PC, where it is part of Sonic 3 & Knuckles. Sega delisted several older standalone versions ahead of its release.

Sales & reviews

Sales figures

Sega has said Sonic 3 and Sonic & Knuckles sold more than four million copies between them. In the United States alone, Sonic & Knuckles had sold about 1.24 million by January 2007, slightly ahead of Sonic 3.

• 4m+with Sonic 3 (Sega)
• 1.24min the US by January 2007
• $45mmarketing budget at launch

Reception and review scores

Period reviews from Sega Retro’s index of magazine scans; scores not out of 100 are shown as Sega Retro converts them.

GamePro gave it a perfect score. Mean Machines Sega was cooler than on Sonic 3, at 85% against 94%, and among the scores listed here Next Generation was the least impressed, at the equivalent of 75% (Sega Retro’s full table has a few lower ones).

Honours

Reader reviews

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Further reading

More from Sonic Scene:

Sources

Every fact on this page was checked against the sources below. Sonic Retro and Sega Retro are linked through the Wayback Machine copies we read (the live sites sit behind a bot check). Magazine scores come from Sega Retro’s review index, which links each score to a scan of the original page.

• Overview: Sonic Scene, “Sonic and Knuckles (Genesis / Megadrive version)” and “Sonic & Knuckles” (original articles, 2017); Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro, Sonic & Knuckles/Development (the split, promotion); Sega Retro, Sonic & Knuckles (release dates, prices, product codes, digital releases, magazine scores with scans)
• Quick Answers: Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone; Sonic Retro, Sonic & Knuckles/Hidden content; Sega Retro, Sonic & Knuckles (release dates, prices, product codes, digital releases, magazine scores with scans); GamesBeat, “Sonic Origins gets a June 23 release date” (2022); GamesRadar, “Sega delists classic Sonic games ahead of Sonic Origins launch” (2022)
• Plot / Story: Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone; Sonic Retro, Eggrobo; Sonic Scene, “Sonic and Knuckles (Genesis / Megadrive version)” and “Sonic & Knuckles” (original articles, 2017)
• In comics, TV & other media: Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone
• Characters: Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone; Sonic Retro Badnik pages: Butterdroid, Cluckoid, Dragonfly, Madmole, Mushmeanie, Blaster, Technosqueek, Skorp, Sandworm, Rock’n, Hyudoro, Iwamodoki, Fireworm, Toxomister, Spikebonker, Chainspike; Sonic Retro, Eggrobo; Sega Retro, Sonic & Knuckles/Production credits
• How it was made: Sonic Retro, Sonic & Knuckles/Development (the split, promotion); Sonic Retro, Sonic the Hedgehog 3/Development (Rock the Rock); Wikipedia, “Sonic & Knuckles” (Development and Release: the split, the lock-on adapter, the $45 million campaign, the Alcatraz tournament); Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases)
• Firsts: what this game introduced: Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone; Sonic Retro, Eggrobo
• Cheats & secrets: Sonic Retro, Sonic & Knuckles/Hidden content; Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone
• Glitches, exploits and oddities: Sonic Retro, Sonic & Knuckles/Bugs; Sonic Retro, Sonic the Hedgehog 3/Bugs (vertical wrap)
• Videos & media: YouTube, SEGA (official channel), video pSickJDSSgk (checked with oEmbed, 5 Nov 2026); YouTube, Sonic the Hedgehog (official channel), video FoyoWlOJILc (checked with oEmbed, 5 Nov 2026); Gematsu, “Sonic Origins Plus announced” (March 2023)
• Trivia & facts: Sonic Retro zone pages: Mushroom Hill Zone, Flying Battery Zone, Sandopolis Zone, Lava Reef Zone, Hidden Palace Zone (Sonic & Knuckles), Sky Sanctuary Zone, Death Egg Zone (Sonic & Knuckles), The Doomsday Zone; Sonic Retro, Eggrobo; Sonic Retro, Sonic & Knuckles/Development (the split, promotion)
• Legacy: Sonic Scene, “Sonic and Knuckles (Genesis / Megadrive version)” and “Sonic & Knuckles” (original articles, 2017); Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sega Retro, Sonic & Knuckles (release dates, prices, product codes, digital releases, magazine scores with scans); GamesBeat, “Sonic Origins gets a June 23 release date” (2022); Gematsu, “Sonic Origins Plus announced” (March 2023); GamesRadar, “Sega delists classic Sonic games ahead of Sonic Origins launch” (2022)
• Sales & reviews: Sega Retro, Sonic & Knuckles (release dates, prices, product codes, digital releases, magazine scores with scans); Sega Retro, Sonic & Knuckles Collection (PC release dates); Sonic Retro, Sonic & Knuckles (story, gameplay, Lock-On, adaptations, re-releases); Sonic Retro, Sonic & Knuckles/Development (the split, promotion); Wikipedia, “Sonic & Knuckles” (Development and Release: the split, the lock-on adapter, the $45 million campaign, the Alcatraz tournament)