Video Game / Sonic 3 & Knuckles

An adventure so big, one cartridge wasn't enough.

"Sonic races through the green fields.
The sun races through a blue sky filled with white clouds.
The ways of his heart are much like the sun. Sonic runs and rests; the sun rises and sets.
Don't give up on the sun. Don't make the sun laugh at you."

— Sonic & Knuckles Japanese box art

Sonic 3 & Knuckles is Sega's third 16-bit entry in the Sonic the Hedgehog series, and the follow-up to the wildly-popular Sonic the Hedgehog 2. It was so ambitious that time and hardware constraints forced them to split it into two separate games:

Sonic the Hedgehog 3, originally released on February 2, 1994,^note Groundhog Day, so the launch date was naturally referred to as "Hedgehog Day" in Sega's marketing covers Sonic's arrival at the Floating Island and his journey to Launch Base Zone. As in Sonic 2, players can control Sonic the Hedgehog, Miles "Tails" Prower, or both. Knuckles the Echidna, an eventual member of the series' Power Trio, made his debut in this game as an antagonist. It was the first Sonic game to offer save files.

The plot picks up after the Genesis/Mega Drive version of Sonic 2. Following the destruction of the Death Egg at the end of the previous adventure, it crash lands onto the mysterious Floating Island above the sea, taking Dr. Eggman (a.k.a. Dr. Robotnik) with it. The island is able to fly due to its connection with the Master Emerald, a powerful gem said to control the Chaos Emeralds. Due to the impact of the Death Egg, though, the island has sunken into the ocean. Eggman is miraculously unharmed, and finds himself at the Master Emerald's altar.

Realizing the gem's potential, Eggman decides to use the Master Emerald as a power source to re-launch the Death Egg. Unfortunately, he runs into the Emerald's guardian: Knuckles the Echidna, the last survivor of the ancient echidna clan that once ruled the Floating Island. Knuckles is very naïve due to living in isolation all his life, so Eggman gets an idea. He tricks Knuckles into believing Sonic and Tails are thieves out to steal the Master Emerald. Knuckles agrees to work for him to protect the Emerald, allowing the doctor to hatch his plans in secret.

When Sonic and Tails arrive to investigate the now sea-bound landmass, the former is attacked by Knuckles, who proceeds to be a thorn in his side throughout the entire game. The game ends with Sonic preventing Eggman's Death Egg from launching, which causes it to plummet back into the island's volcano.

Sonic & Knuckles, officially released worldwide on October 18, 1994, continues Sonic's adventure after he arrives on Mushroom Hill and up to the final battle against Eggman aboard the Death Egg. As the title suggests, Sonic and Knuckles are the only playable characters. S&K was originally released on October 17 in select U.S. retailers and via the MTV-televised "Rock the Rock" competition (which concluded on Alcatraz Island, of all places), where the first cartridges were given to the winner and runner-up. One of the game' main selling points was its "Lock-On Technology", i.e. a slot on top of the cartridge in which another Genesis cartridge could be inserted. By connecting the Sonic 3 and S&K cartridges in this way, the two could be played as one continuous game: Sonic 3 & Knuckles, a 32-Megabit^note the box claims 34-Megabits, but two of those megabits actually belong to the unrelated Sonic 2 lock-on feature, which is 26-Megabits game with all three playable characters.

In the second act, Sonic races against Eggman to stop him from launching the Death Egg once again. His campaign culminates in a battle against Knuckles just outside the Master Emerald's altar. When Eggman shows his true colors by stealing the Emerald and electrocuting Knuckles when the latter tries to interfere, the echidna finally realizes the doctor's trickery and helps Sonic chase after the Death Egg before it can leave orbit.

The Knuckles campaign takes place shortly after Sonic's story and features the same levels up to Lava Reef Zone. After that, the player explores an abridged version of Hidden Palace Zone that is devoid of obstacles, which is followed by the final battle against Super Mecha Sonic, an Emerald-enhanced version of Sonic's robotic rival, on Sky Sanctuary Zone. Knuckles can't run as fast or jump as high as Sonic and Tails, but can access new areas by gliding and plowing through walls that the others can't pierce. The villain is one of Eggman's Eggrobos, rather than the Doc himself.

The gameplay represented further Sequel Escalation compared to Sonic 2. The top speeds are even faster, Zones are larger and have a greater variety of terrain, and nearly every Act ends in a boss fight. There is slightly more focus on plot, as well: Knuckles' arc is shown through a number of in-game, dialog-free cutscenes, and each Zone ends with a brief scene of the heroes getting transported to the next region in some fashion.

The game also introduces specialized shields: the Water Shield lets you freely explore underwater sections without drowning and grants Sonic the ability to bounce; the Flame Shield renders you impervious to flames and lava and lets Sonic perform a flying tackle; and the Lightning Shield attracts rings like a magnet and gives Sonic a double jump, as well as protecting you from electricity-based attacks. Item-granting Bonus Stages were added along with the usual Special Stages, and both are awarded in-level as opposed to in-between them. Cast Speciation (first introduced in the previous year's 8-bit title Sonic Chaos) was further developed: Sonic can make use of a brief, midair "Insta-Shield" to deflect hits and extend his reach slightly (useful against badniks that have a shield around them); Tails can fly (by himself or while carrying Sonic) and swim; and Knuckles can glide and attach to, and climb, sheer walls.

S&K also linked with the Sonic 2 cartridge, allowing you to play Knuckles in Sonic 2. The developers attempted to implement a similar feature with Sonic 1, but found that Knuckles' color palette was incompatible with the game's. Instead, combining it with Sonic 1, or the '97 compilation cart Sonic Classics, expands on the Special Stage (Blue Sphere) minigame, with over 100 million variations. Locking on any other Genesis game will generate a unique stage.

For the first time since 2011, Sonic 3 & Knuckles has been re-released in the Compilation Re-release Sonic Origins, developed by Simon "Stealth" Thomley of Headcannon, who was previously responsible for the rereleases of Sonic 1, Sonic 2, and Sonic CD as well as Sonic Mania. Much like those games, Sonic 3 & Knuckles has been rebuilt in the Retro Engine developed by Christian Whitehead. In addition to upgrades comparable to the other Retro Engine rebuilds, this release is also notable for another reason: due to, to put it lightly, complicated legal issues regarding the game's soundtrack (see the Trivia page for the full details), a few of the music tracks have been replaced with Genesis-faithful arrangements of tracks that were originally used in a prototype version of the game and would later be implemented into Sonic & Knuckles Collection, a 1997 PC release of the game. Jun Senoue, who worked on the original game's soundtrack, is said to be responsible for these arrangements, though there's dubiousness with that.^note It's speculated that these are actually even earlier prototype versions than what was leaked, due to some telling details, Ice Cap Zone's music being almost identical to the leak's and how every other attempt by Senoue to sound Genesis-authentic ends up sounding like it came out of Sonic the Hedgehog 4, including the confirmed new Super theme.

This would be the last core series Sonic game until 1998's Sonic Adventure, which further explores Angel Island's backstory. It would later get two more sequels in Sonic the Hedgehog 4 (its plot serving as a sequel to the Death Egg saga) and Sonic Mania (unrelated plot-wise, but closer in gameplay and formula, due to taking place in the Classic Sonic period after the Time Eater plot in Sonic Generations).

Elements of this game (and Sonic the Hedgehog 2) would get loosely adapted in the film Sonic the Hedgehog 2 (2022).

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Sonic 3 & Knuckles provides examples of the following & Knuckles:

#-G

• Absurdly Short Level: Knuckles' version of Hidden Palace Zone is around 13 seconds long and contains no hazards, consisting only of him running to the teleporter that takes him to his version of Sky Sanctuary Zone (a Boss-Only Level against a surviving Mecha Sonic).
• Action Bomb: Iwamodoki/Fake Rock in Lava Reef Zone will self-destruct after a few seconds.
• Adaptational Explanation: In the original (and its locked on version), the entrance platform to the Death Egg seemingly detaches from the handle after the battle with the Big Arm for no reason, despite the Egg Mobile simply falling down. In Origins and its re-release, the Big Arm crashes on the center of the platform (destroying its outer shell and exposing the Egg Mobile in the process), causing the handles supporting it to be destroyed due to its impact.
• Advancing Wall of Doom: There's a higher concentration of "keep moving or die" scenes here than in any other Sonic game:
  • The wall of doom at the beginning of Hydrocity Zone Act 2.
  • The altering landscape at the end of Marble Garden Zone Act 2.
  • The rising water level in Knuckles' version of Launch Base Zone Act 2. Though in this case, the main hazard isn't being crushed, but rather drowning.
  • The auto-scrolling Jet Mobile boss fight in Mushroom Hill Zone Act 2. You can't actually be crushed or go off the screen here, though you may be dragged into spikes if you don't bother to jump.
  • The crumbling airship at the end of Flying Battery Zone Act 2.
  • The rising sand sequences in Sandopolis Zone Act 2. The boss of the level, Egg Golem, is an advancing sphinx-mecha, which crushes you against a wall if you take too long to defeat it.
  • The pre-boss fight forced-scrolling scene in Lava Reef Zone Act 2. Again, this isn't going to crush you, though it may drag you into a Bottomless Pit.
  • Dr. Eggman's screen-filling, inexorably advancing mecha in Death Egg Zone Act 2. After defeating it, you chase his mobile, carrying the Master Emerald, while the platform collapses behind you.
  • The entirety of The Doomsday Zone.
  • One of the three Bonus Stages features this, with a glowing, upward-climbing double helix that ends the level if you touch it.
• Airborne Aircraft Carrier: Flying Battery Zone takes place in one. Curiously, the aircraft makes its first appearance in Angel Island Zone, when it tries to bomb Sonic near the end of Act 2.
• Airborne Mook: This game features the most all of the Genesis games.
• Alphabetical Theme Naming: The 2-player stages: Azure Lake, Balloon Park, Chrome Gadget, Desert Palace, and Endless Mine.
• Always Over the Shoulder: In the Special Stages, the view is locked behind the character, and the camera turns in sync with the player.
• Amusement Park of Doom: Carnival Night Zone is very literal in the minds of many when you consider the drum. Averted by Balloon Park from the 2-player mode, which has no hazards.
• Ancient Egypt: Sandopolis Zone is ancient Egypt on the Floating Island.
• And I Must Scream: Subverted. When you beat Lava Reef Zone Act 2's Hot Mobile boss, Dr. Eggman sinks into the lava, which cools and hardens seconds later, seemingly trapping him inside. After the Knuckles fight in Hidden Palace Zone, though, he's shown to be perfectly fine.
• Antepiece:
  • Carnival Night Zone has one poorly thought-out example. During Act 2, the player can come across a barrel that can be swung up and down, eventually letting the player access a higher floor. Later, the game locks the player in a room with a similar barrel (known among the fanbase as the "Barrel of Doom"), which must be swung in the same way, so the player can access a lower floor. What's the issue here, besides the controls of the barrel not being obvious to the player? The first barrel, the antepiece, is completely optional, since the player can get upstairs using a character power or take another route entirely and never have to deal with the barrel or even know it exists (you can also propel yourself high enough with the barrel with well-timed jumps, the only action that gives immediate feedback); the Barrel of Doom, on the other hand, cannot be bypassed.
  • An earlier one in the same zone has a barrel that you can manipulate downwards to access an extra life, but this one also fails to be a workable Antepiece because you can jump off it just low enough to avoid the anti-gravity platforms above.
• Anti-Climax: The standalone Sonic 3 ending is very much this, especially compared to the ending of the previous installment: Launch Base Zone is nowhere as sinister or menacing as Scrap Brain Zone or Metropolis Zone, the recurring villain Knuckles is disposed of in a cutscene where Sonic does absolutely nothing, and the final battle ends with the Death Egg exploding moments after taking off. This is fixed, however, by locking the game on to Sonic & Knuckles, making Launch Base Zone the halfway point of the game, retconning the explosion of the Death Egg, and featuring a confrontation with Knuckles and his Heel–Face Turn, as well as a memorable Astral Finale.
• Anti-Villain: Thanks to Eggman lying to him, Knuckles serves this role until Hidden Palace Zone.
• Another Side, Another Story: Subverted. Contrary to what the American Sonic & Knuckles manual implies, Knuckles' adventure actually takes place after Sonic's, as the game itself hints at various points:
  • Knuckles' archnemesis is an Eggrobo, which are enemies that are only shown being activated and deployed late into Sonic's story during Sky Sanctuary Zone. Sonic's Good Ending also ends in a Sequel Hook with an Eggrobo rising out of a pile of trashed enemies, clearly implied to be the one that harasses Knuckles.
  • The backgrounds of Angel Island Zone Act 1 and Sky Sanctuary make it clear that the Floating Island is currently in the sky, whereas it was on the sea during Sonic's story, rising only in the Good and Best Endings of this one.
  • In Sandopolis Zone Act 2, while playing as Sonic, the ghostly Hyudoro enemies do not appear until they are inadvertently set free by Sonic breaking open their capsule. Whereas for Knuckles, the capsule has already been broken by the time he finds it, and the Hyudoros themselves appear as soon as the level starts.
  • The Death Egg is nowhere to be seen in Launch Base, Lava Reef, and Hidden Palace, hinting that it has already taken off.
  • When Sonic defeats Mecha Sonic in his version of Sky Sanctuary, Mecha Sonic notably doesn't fall apart like the other mecha bosses. This sets up its return at the end of Knuckles' game.
• Anti-Frustration Features:
  • Tails normally has limited flying stamina, but that limitation is suspended while fighting Eggman in Marble Garden Zone Act 2, where he'll keep flying for the duration of the Jet Drill boss fight, even if it takes 10 minutes.
  • In Sonic 3 & Knuckles, many of the traps in the Sonic 3 levels have been removed, making most of the levels, particularly Carnival Night and Launch Base, much quicker and easier.^note The Complete Game Mod restores many of these to their Sonic 3 layouts. In addition, all completed files from Sonic 3 can continue on from Mushroom Hill Zone instead of starting the game all over again.
  • The remastered version in Sonic Origins makes a few adjustments for a less frustrating experience:
    • An AI-controlled Tails no longer inhales air bubbles while underwater, which prevents him from stealing them from Sonic.
    • Tails can now carry Sonic in the air in single-player mode, which was something that required a second controller in the Genesis version.
    • Characters can now look up and down while standing on any barrels of doom, which makes them a lot less confusing.
    • Tails can now use the Chaos Emeralds to turn into Super Tails.
    • In Anniversary Mode, if you fail a Chaos Emeralds special stage, you are offered the opportunity to immediately try again at the cost of one coin.
• Art Evolution:
  • Owing to being a late Genesis game, the game incorporates a lot more depth and detail into the zones compared to previous 2D Sonic games, as well as more 3D-esque set pieces and unique act backgrounds for most of the zones (with some zones having their backgrounds change mid-zone, such as Angel Island Act 1 and Mushroom Hill Act 2).
  • Sonic's sprite also looks noticably more detailed compared to the simpler sprite he had in previous games, giving him more a CG-like appearance with smaller eyes, detailed gloves and rounded looking shoes. Tails and Dr. Eggman have recieved some changes too (such as more detailed eyes and new shading), but presumably due to the game being rushed, their sprites remain mostly identical to previous appearances, which makes them stick out like a sore thumb when compared to the more detailed sprites Sonic and Knuckles have.
• Artistic License – Physics:
  • Granted, the game was never meant to be physically realistic, but one notable point is that the Bomber Starship, the second phase of The Doomsday Zone's Final Weapon, implies the presence of drag in space, given that the ship shoots bombs forward, that then slow down and fall behind.
  • In Knuckles' best ending, the Master Emerald lifts the Floating Island to the edge of space... putting that aside for a moment, anything that high up will quickly asphyxiate due to the low air pressure (for the same reason that you can't survive atop Mt. Everest, assuming you don't freeze to death first).
• Artwork and Game Graphics Segregation: As an NPC, Knuckles has an alternate palette that gives him pink fur and yellow socks. His sprites as a playable character are more accurate to his intended design — red fur and green socks. Oddly, this is consistent even when playing both games locked on. It seems this is due to palette limitations — early builds of Sonic 3 have shown that if Knuckles' socks were green, the normally yellow text of the Heads-Up Display would be green as well◊, and having the text turn green whenever Knuckles showed up would have been jarring.
• Astral Finale: Death Egg Zone and The Doomsday Zone take place in space.
• Attack Drone: As Super Tails, Sonic 3 & Knuckles only (or Hyper Tails for Origins), the golden Flickies that follow him serves as such, immediately attacking any enemy or boss that's onscreen.
• Audible Sharpness: For the first time, you can hear Tails using his tails as rotary blades, and weaponize them, which is the only way Tails can beat the Marble Garden Zone Act 2 boss when on his own.
• Background Boss: The first part of the final boss of Death Egg Zone. The Giant Eggman Robo stands in the background, but attacks you with Giant Hands of Doom.
• The Bad Guy Wins: Regardless of the ending, Eggnan wins in Sonic 3.
• Bag of Spilling: The opening cutscene shows Super Sonic briefly before Knuckles punches the emeralds out of him and takes them away.
• Bait-and-Switch Boss: Knuckles' version of Sky Sanctuary opens with Eggrobo attacking. Then Mecha Sonic shows up and (unintentionally) destroys it.
• Batman Can Breathe in Space: Death Egg Zone Act 2 and The Doomsday Zone take place in space. Sonic can inexplicably survive without oxygen, even outside of his Hyper form.
• Because Destiny Says So: The mosaics in the background of Hidden Palace Zone are clearly a stylized depiction of Super Sonic's fight with the final boss in The Doomsday Zone.
• Bedsheet Ghost: The Hyudoros in Sandopolis Zone Act 2. The stage's main gimmick is that Sonic must activate light switches to prevent them from attacking him. The spirits start out as cute white sprites, but get progressively more menacing as the lights fade out, and once the lights go out completely, they start attacking him in groups.
• Berserk Button: The second stage of Death Egg Zone Act 1's boss, Red Eye, seems to have one: it will start spinning a pair of spiked platforms extremely rapidly while firing off a massive laser beam if you attack it. It even bobs up and down once just before returning to its normal motion, as if it had to regain its composure.
• Big Boo's Haunt: Sandopolis Zone Act 2; the Hyudoro ghosts pester (and eventually hurt) you if you don't keep the lights on.
• Bittersweet Ending:
  • In the bad ending of Sonic 3 by itself, Sonic and/or Tails stop the relaunch of the Death Egg and destroy it, but Eggman gets away with the remaining Chaos Emeralds the player hasn't collected, thanks to Knuckles still working with him.
  • Sonic's bad ending in Sonic & Knuckles, as well as his and Tails' bad endings in Sonic 3 & Knuckles. The Death Egg has been soundly destroyed, but Eggman was able to get away with the Master Emerald, and the Floating Island is still stuck at sea.
  • Knuckles' bad ending. While the Eggrobo that harassed the Echidna is destroyed and Eggman's activity on the island is no more, the Floating Island falls back into the ocean and as revealed in The Stinger, the Master Emerald is now in the possession of Mecha Sonic.
• Blackout Basement: Carnival Night Zone Act 2 (for Sonic and Tails), and Sandopolis Zone Act 2 without the outside lighting.
• Bonus Stage: Unique among Sonic games for having two types:
  • "Special Stages:" A 3D maze where you must "Get Blue Spheres". Finishing earns you a Chaos Emerald. Accessible via giant rings hidden in the levels.
  • "Bonus Stages:" Stages for collecting rings and powerups. Accessible via a circle of stars that appear if you pass a star post with 20 or more rings, much like the Special Stages in Sonic 2. There are three types, and all three are in play in the locked-on game:
    • A giant gumball machine that Sonic can turn by bouncing back and forth on platforms that then disappear. Each gumball represents different power-up items (rings, shields, extra lives, etc). There's a set of springs at the bottom that break away when you hit them; they can be restored with one of the gumballs, but falling past it ends the stage. This is the only Bonus Stage in Sonic 3 alone.
    • A 360-rotating area that is a Genre Throwback to the Sonic 1-style Special Stages with most of the same blocks, except with a Casino Night-esque slot machine (and similar results including losing rings if you end up getting three Eggmen) in the center of the stage instead of a Chaos Emerald. The corners each have goal zones, and rolling on one of the blocks on the border changes its color; after three changes, it becomes a goal block; you eventually need to hit a goal to leave. Present in Sonic & Knuckles standalone.
    • A pinball-type arena with a glowing, upward-climbing double helix at the bottom that continuously rises upward. This is the only of the three stages that the player can "beat" by reaching the top of the stage before getting caught in the helix. In order to move up, Sonic has to fling off energy spheres, and the smaller bubbles release the gumball prizes, which rise up and away; the higher up you get, the better the prizes. Present in Sonic & Knuckles standalone.
• Book Ends: The game begins with Sonic flying towards Floating Island by plane and ends with him leaving. By collecting all Emeralds, Sonic also brings the Master Emerald back to Knuckles, who had taken the Chaos Emeralds from him in the beginning.
• Boring, but Practical: Sonic's Insta-Shield looks pretty underwhelming compared to the abilities of Tails and Knuckles, which allow far more expansive exploration and Easter Egg locating. However, when mastered, its split-second invincibility can make obstacles and bosses a breeze.
• Boss-Only Level:
  • The Doomsday Zone is a bonus level dedicated entirely to Sonic's battle against the True Final Boss.
  • Knuckles's version of Sky Sanctuary consists of his last two bosses and no platforming whatsoever.
  • From a gameplay perspective, Sonic's version of Hidden Palace Zone only contains a few minor spike hazards and a mini-boss fight against Knuckles.
• Boss Rush: Sky Sanctuary Zone features a rehash of bosses from previous games at the end of each of its segments.
• Bottomless Pit Rescue Service: In the Marble Garden Zone Act 2 boss, Jet Drill, Tails will automatically rush to pick up Sonic should he fall offscreen.
• Brick Joke: As you run through Launch Base Zone Act 1, you'll eventually find Dr. Eggman carrying some sort of box around. That's the Act 1 boss, Twin Hammer. When you defeat it, you might notice there are another two boxes in the wall. Those are the ones Knuckles will later fight in his version of the level.
• Brutal Bonus Level: There is a secret Special Stage in Sonic 3 that can be played from the sound test menu and it is rough, requiring very skilled handling to not prematurely jump or turn, especially towards the end when the stage is running at max speed. Sonic & Knuckles has an extra Special Stage of its own but it's far easier (and somewhat sparse). Both of these stages were resurrected for Sonic Mania's bonus stages, with the only change being to the Sonic 3 stage, replacing a few spheres with rings.
• Bubble Shield: The "Water Shield" is the Trope Codifier, encasing the user in a bubble that allows them to breathe underwater and bounce high into the air.
• Build Like an Egyptian: Sandopolis Zone Act 2 is set inside a haunted pyramid.
• But Thou Must!:
  • There is no way to avoid freeing the Hyudoro ghosts in Sandopolis Zone Act 2; it's past a loop with a chute below it that forcibly drops you onto the Capsule holding them, and there are no other routes for Sonic and Tails to take (the Hyudoros are already waiting for Knuckles, who has more choices for routes at the start of the act). Even if you use glitches or Debug Mode to move past the capsule without pressing the button, the game will eventually decide you ought to have pushed the button by now and magically let them out anyway if you hit a Star Post.
  • In the Origins version, the last spinning top before the junction between Sonic/Tails' and Knuckles' paths in Marble Garden Zone Act 2 has its behavior altered so that it is automatically dismounted before the Strange Relief (arrow-shooting statue that needs to be broken in order to open a path) that's normally too high for Knuckles to hit, preventing him from proceeding to Sonic and Tails' route. Even if it is possible to break out of the automated path as Super/Hyper Knuckles at one point, the game still forces the player off it in the same spot for no discernable reason.
• Cap: Unlike the previous Genesis Sonic games (including Sonic CD), Sonic 3 and Sonic & Knuckles finally did away with having a speed cap at all, allowing the characters to run at full speed while still pressing forward without slowing down in midair.
• Cast Speciation: Back in Sonic 2, Sonic and Tails controlled the same way. Here, the player can actually make Tails fly to skip platforming areas. Meanwhile, Sonic can trivialize quite a few tough enemies and bosses with the invincibility on his Insta-Shield. On top of that, the elemental shields grant him useful mobility options. Like Tails, Knuckles' gliding and climbing abilities make him useful for platforming, but his low jump can make certain spots more difficult to overcome. The lowered jump height of Knuckles is actually used to seal off Sonic/Tails-only parts of levels, while the reverse is often accomplished via gliding, wall climbing, or breaking walls that only Knuckles can destroy.
• Chekhov's Gun:
  • The breakable objects that Knuckles could break through to reveal alternate paths through the levels were this in the standalone Sonic 3, as the player could clearly see pathways behind some of them, but had no way to get there until Sonic & Knuckles was released.^note While it's possible to use the Debug Mode to access Knuckles' paths, doing so in Sonic 3 will often result in you hitting a kill plane because the scripts for these areas don't exist in the standalone game.
  • The Japanese manual for Sonic 3 states that Knuckles knows of the prophecy found in the Hidden Palace and that the Death Egg is an omen, comparing it to the egg of the prophetic dragon.
• Circling Birdies: Happens to Knuckles after Dr. Eggman shocks him in Sonic's version of Hidden Palace Zone.
• Circus Synths: The music for Carnival Night Zone Act 1 and Act 2, aside from being played on the Genesis' 16-bit sounds, were based on Michael Jackson's pop music.
• Climax Boss:
  • The third and final boss of Launch Base Zone Act 2, Big Arm, becomes this in the Sonic Origins remaster, marking the end of the game's first half^note in the original Genesis version of the full game, the second boss, Triple Score, serves this role instead, though Big Arm is still kept for Knuckles' playthrough. It's also a turning point in the story, as it's when Sonic stops the relaunch of the Death Egg, knocking it down to the Floating Island's volcano and setting in motion the Sonic & Knuckles portion of the story.
  • The fight against Knuckles in Hidden Palace Zone. While he's by no means difficult, it represents the point in the story where the two rivals finally engage in personal combat. Plus, immediately after the fight is done, Eggman's villainy is exposed when he steals the Master Emerald, Knuckles does a Heel–Face Turn in showing Sonic the way forward, and the game's final act begins.
• Coconut Meets Cranium: Like its predecessor Ai Ai/Coconuts, the Monkey Dude badnik throws coconuts at the player's character, which can hit them on the head if they're not careful.
• Collision Damage:
  • Sonic inflicts this on enemies in his Super and Hyper forms. Even bosses die if Sonic simply touches them long enough.
  • When fighting Knuckles, he'll normally punch you if you walk on him. However, if you recover a ring and walk into him again until your invincibility fades, you'll see that he's actually coded to take damage from mundane contact.
• Colony Drop: This is what sets the game's events into motion. At the end of the previous game, Sonic knocked Eggman's Death Egg out of orbit. As we learn from the prologue in this game's manual, this led to it crash-landing on the Floating Island, knocking it out of the sky and eventually alerting Sonic and Tails, as they detect a strong energy signature resembling Chaos Energy coming from its direction some days later. A second, smaller one happens between 3 and & Knuckles, as the Death Egg falls back onto Floating Island after being disabled, this time lodging itself in a mountain.
• Comic-Book Adaptation: In both Sonic comics:
  • The Archie comic had a short adaptation of Sonic the Hedgehog 3 in issue #13, and also a 48-page special based on Sonic & Knuckles. Both were loose adaptations that excluded major elements such as the Death Egg. Complaints from fans led to Archie releasing a mini-series featuring the Death Egg later on.
  • Sonic the Comic had Robotnik's second Death Egg being stuck on the Floating Island for the span of about 19 issues, the first four of which adapted the plot of Sonic the Hedgehog 3, and the last five of which were based on the closing levels of Sonic & Knuckles.
• The Computer Is a Cheating Bastard:
  • Inverted in Hidden Palace Zone: In Sonic 3 & Knuckles, Sonic can be airlifted by Tails to a hidden area where there are 30 extra rings. With those and the other rings that aren't hidden, Sonic can turn into Super Sonic or Hyper Sonic for the Knuckles battle.
  • When Tails transforms, as any boss or enemy (except Knuckles) will get pecked to death by Tails' Super Flickies.
  • Without the 7 Chaos/Super Emeralds, however, Knuckles plays this straight; his Spin Jumps and Spin Dashes take priority over Sonic's, and he can block your Spin Dashes by crouching. You can't block his. When he's attacking with a glide, however, you can hit him nearly anywhere that isn't his fists. Oh, and he can jab you in the face if you walk too close to him and he's not attacking you.
• Conspicuous Electric Obstacle: Death Egg Zone has very obviously electrified floor and ceiling hazards. With a lightning shield, they are harmless.
• Continue Your Mission, Dammit!:
  • See Idle Animation, but also, after Knuckles lowers the bridge for you in Sky Sanctuary Zone, ducking next to him makes him look at your character and wave his arm, as if telling you to go on without him.
  • In Sonic's continue screen, Tails tugs at his arm while pointing forward.
• Continuing is Painful: The final boss of the Death Egg Zone, Giant Eggman Robo, in Sonic 3 & Knuckles or just Sonic & Knuckles. If you die, you have to fight the boss with no rings and no shield. What makes it worse is that the level itself is long, increasing the chances of that. Averted, however, if you are Tails, because Tails can fly over the laser beam and not have to worry about being hit (one of two advantages that Tails has here; the other is that if Tails has sufficient rings, he can call in the flicky reinforcements of Super Tails to make quick work of this boss).
• Conjoined Eyes: Particularly noticeable on the Sonic the Hedgehog 3 title screen, in which the middle of Sonic's brow actually lowers to separate his eyes whenever he winks.
• Continuity Nod: Many details and changes in scenery make it clear that, mess-ups aside, Knuckles's story takes place after Sonic defeats Dr. Eggman.
• Convection, Schmonvection: Two-thirds of Angel Island Zone is in the middle of a massive forest fire, yet the characters don't seem to mind. And naturally, Lava Reef Zone's lava only hurts you if you actually touch it.
• Conveyor Belt o' Doom: Death Egg Zone has elevators with conveyor belts that reverse direction each time you jump and try to force Sonic into spikes or gun turrets.
• Co-Op Multiplayer: As in the previous game, a second player can control Tails when playing as Sonic and Tails in single player, the difference being that Player 2 can now fly with Tails as well as pick up Sonic and carry him around.
• Covers Always Lie: The North American Sonic 3 box art features Robotnik setting Angel Island Zone on fire in the background. In-game, however, it's the boss of Angel Island Zone Act 1 who is actually responsible for doing this.
• Cutscene Power to the Max:
  • In the opening cutscene of Sonic's story, Knuckles manages to knock the Chaos Emeralds out of Super Sonic. He can't repeat this feat in his eventual boss fight, as you can become Super Sonic, run up to him, and watch him get KO'd.
  • In Knuckles's best ending, he changes into his Super/Hyper form with no more than three rings, catches the Master Emerald in midair, and holds it with one arm while balancing on a tiny plane thousands of feet in the air.
• Cutting Off the Branches: When playing as Sonic, the opening of this game makes it clear that he did collect all the Chaos Emeralds in Sonic 2.
• Darkness Equals Death: Sandopolis Zone Act 2, once the Hyudoros are released. They become scary-looking and start to attack the player non-stop a little bit after the area is in complete darkness. Grab a light switch to prevent this from happening.
• Damn You, Muscle Memory!: In most 2D platformers that contain Gravity Screw segments, the "up" and "down" controls get reversed along with the gravity. However, whenever gravity is reversed in Death Egg Zone, the controls for looking up and crouching are still up and down respectively, which will likely throw off at least a few new players. Interestingly, Yuji Naka has claimed that fans were surveyed prior to the game's release about whether the controls should be reversed in those particular segments, and that the majority voted to not change the controls.
• Deadly Disc: Carnival Night Zone's miniboss releases a circular saw blade that ricochets around the arena. It can crush Sonic if it lands on him and gradually destroys the floor until there's nothing left for him to stand on except the blade itself.
• Death Mountain: Marble Garden Zone.
• Deflector Shields: Each and every elemental shield is capable of deflecting small projectiles from enemies, or outright disintegrating them with regards to the Star Pointer badniks from IceCap Zone.
• Degraded Boss: A lookalike of Tunnelbot, the Marble Garden Zone Act 1, appears as the Rock Drill, a scaled-up jackhammer bot for a single cutscene in Lava Reef Zone Act 1. Though more imposing, all it does is make the floor collapse — and in Sonic's and Tails's version of the level, the bot falls into lava and blows up immediately after.
• Demoted to Extra: Tails in standalone Sonic & Knuckles, where he only appears in the closing cutscene if the game is played as Sonic. The Japanese manual even notes that he went missing, presumably separated from Sonic after Launch Base Zone.
• Determinator: Given how many mechs he goes through, Dr. Eggman certainly comes off as this in the Death Egg and The Doomsday Zones. He simply will not give up the Master Emerald.
• Developer's Foresight:
  • While most of the environmental hazards of the game can be rendered harmless with the right shield, using the wrong shield in certain areas will cause the player to lose it. For example, the player will lose the Lightning or Flame Shield when they enter an underwater area.
  • If you somehow manage to access Knuckles's boss in Marble Garden Zone Act 2 as Sonic or Tails, Dr. Eggman will be the one riding the Jet Drill, not Eggrobo. Likewise, if you use the Debug Mode to get Knuckles to Sonic and Tails's boss, Tails will still be there to carry the echidna.
  • There is a proper Eggrobo boss for Knuckles in Carnival Night Zone Act 2, if you can access it.
  • In Launch Base Zone Act 2, when playing as Knuckles, if Debug Mode is used to reach the part where Sonic steals one of the Egg-O-Matics, it will result in the NPC Knuckles not appearing in the cutscene should you cause the playable Knuckles to ride it to Sonic's boss arena. It still reacts as if the NPC Knuckles is still there, however, resulting in it being "knocked back" by an invisible force. This is fully fixed in Origins; Not only does Knuckles fully face the right way when riding the Egg-o-Matic, but the invisible "NPC Knuckles" segment doesn't trigger, instead going straight to the Death Egg launching. Eggrobo will be piloting both of the Sonic-exclusive machines as well.
  • If you use Debug Mode in Origins to put Sonic and/or Tails in Knuckles' Sky Sanctuary, Eggman will be in Eggrobo's place. When Mecha Sonic attacks and destroys the Egg Mobile, Eggman falls off screen using unique (albeit modified from Sonic Mania) sprites that Eggrobo does not use. Wouldn't be right to kill off the main villain, would it?
    • Sonic and/or Tails will also escape the claw through different means, Sonic jumping out of it into a Drop Dash to escape Mecha Sonic while Tails flies over to the other side of the screen. In the original, they both glided over like Knuckles, albeit with glitchy sprites.
  • In the Sonic and/or Tails game, if you exploit the Debug Mode in order to avoid releasing the Hyudoros in Sandopolis Zone Act 2, the game will correct itself when you go to the next checkpoint by spawning them anyway.
• Difficult, but Awesome:
  • Sonic's Insta-Shield. Slightly increases the range at which you can hurt enemies, and allows you to phase though things like projectiles, invincible enemies, and other terrain hazards. It only lasts a split second, though, so good timing is an absolute must.
  • Hyper Sonic, Hyper Knuckles, Super/Hyper Tails and Hyper Amy are this in a nutshell, but for different reasons. It's an unbelievable pain to get them, requiring all 14 Emeralds across two whole games, and if you fail to get all the Chaos Emeralds in the Sonic 3 portion, you're locked out of getting them. If you do manage to obtain all of them, however, you're granted access to Hyper Sonic, Hyper Knuckles, and Super Tails (Hyper Tails in the Origins remaster) and Hyper Amy in Origins Plus, who have their own set of moves and abilities. They also look awesome. But beware that when you activate this, you lose a ring per second.
• Difficulty by Acceleration: Used in the Special Stages.
• Disc-One Final Dungeon: Launch Base Zone, the launch site of the Death Egg. In Sonic 3 alone, Sonic & Tails defeat Eggman and blow up the Death Egg, but in Sonic 3 & Knuckles, the Death Egg simply crashes again, this time on a volcano above Lava Reef Zone.
• Disc-One Nuke: If you know where to find all the Giant Rings and have the skill to complete the Special Stages, you can unlock Super Sonic/Knuckles as early as the Hydrocity Zone Act 2, letting you just blaze through all of Sonic 3 or the first half of the combined game with impunity. Likewise, if you're playing Sonic & Knuckles on its own, there are more than enough Giant Rings throughout Mushroom Hill Zone that will allow you to access Super Sonic/Knuckles before you even leave that zone.
• Divergent Character Evolution: While Sonic and Tails played almost identically in Sonic 2, all three characters have specific abilities that can change the way they're played:
  • Sonic gains extra maneuverability when he has a shield or is Hyper Sonic (he gets a double jump in any direction). His Insta-Shield extends his hitbox, as well. As a result, Sonic is generally played more aggressively and recklessly.
  • Tails has a slightly smaller sprite, and can fly and swim. While flying, his tails become a hitbox, but the rest of him is vulnerable. He cannot go Super with only the Chaos Emeralds, but with the Super Emeralds, he gains homing attack Flickies. Tails is generally played more evasively, circumventing level hazards rather than blazing through them.
  • Knuckles can glide and climb, and has very poor jump height, which makes it necessary for him to punch through rock walls and access special level routes. Because of his poor jump and unfamiliar levels, and the slow initial speed of his gliding and climbing, Knuckles is usually played cautiously and tactically.
• Divided for Publication: Originally designed as a single continuous story, the game was ultimately released as Sonic the Hedgehog 3 and Sonic & Knuckles thanks to a mix of technical issues and a promotional deal with McDonald's; as a result, the Sonic & Knuckles cartridge is designed so that it can be locked onto the Sonic 3 cart, offering the ability to play both games as one.
• Double-Edged Buff: You can't use the special moves of the fire, thunder, and water shields if you are invincible, but you do still get the side benefits of the latter two (attracting rings to you and Super Not-Drowning Skills).
• Do Well, But Not Perfect:
  • If you've collected even one of the Super Emeralds, you're considered to not have a full set of 7 Chaos Emeralds. As such, you can't go Super (if playing as Sonic or Knuckles), although you will still be able to transform into Super Sonic when you reach The Doomsday Zone and get the good ending. Of course, this is downplayed in that doing perfect (i.e. collecting all 7 Super Emeralds) earns you Hyper Mode and the best ending, so it's more like do either mediocre or perfect but not well.
  • There is also an inverted example: if you beat a zone at exactly 9:59 on the timer (which is literally the last possible second, meaning that you took as much time as you possibly could to reach the goal), you get 100,000 points, which is the largest single point bonus in the game and worth two extra lives by itself. So this is "Do Bad, but Not Fail".
• Dreadful Dragonfly: This game introduced the Dragonfly badniks, which have spiky abdomen that they use to skewer Sonic and Knuckles.
• Dropped a Bridge on Him: Eggrobo. After spending the entirety of Knuckles's story as the primary antagonist, he gets destroyed by Mecha Sonic right before the final boss battle begins.
• Dreary Half-Lidded Eye: The Toxomisters in Lava Reef seem to have this.
• Dual Boss: Twin Hammer, the Launch Base Zone Act 1 boss, when playing as Knuckles. While Sonic and Tails only deal with one of them, Knuckles fights two of them and with less room to maneuver. This also occurs briefly for Knuckles in Sky Sanctuary Zone with Eggrobo and Mecha Sonic before the latter accidentally destroys the former.
• Dub-Induced Plot Hole:
  • The English Sonic 3 manual gives no explanation as to why Sonic and Tails traveled to Floating Island, and hints that the game takes place right after Sonic 2, despite Eggman being already having multiple bases on the island. It also states that Knuckles is the guardian of the Chaos Emeralds, and Floating Island uses their power to float, when in actuality it uses the Master Emerald's power (as demonstrated in the Sonic & Knuckles ending and later games), and the Chaos Emeralds were in Sonic's possession at the beginning of the game (not to mention they were present in previous games).^note This seems to have stemmed from a mistranslation. The Japanese manual stated that the Floating Island housed a Chaos Emerald, likely referring to the Master Emerald while avoiding giving away its name before Sonic & Knuckles came out. However, because Japanese doesn't distinguish between singular and plural, it sounded ambiguous enough to be interpreted as plural. Early design documents confirm that it was supposed to be singular.
  • The English Sonic & Knuckles manual implies that Knuckles' story takes place simultaneously with Sonic and Tails' story, despite everything in his story pointing toward it taking place after (see Another Side, Another Story).
  • Non-story example: In the bonus stages, the spheres containing Shields have a B on them, as Shields are called Barriers in Japan. Their sprite wasn't altered to replace it with an S in international releases, rendering the letter nonsensical outside of Japan.
• Dub-Induced Plotline Change: The North American Sonic 3 manual does not elaborate on Sonic and Tails's motivation for visiting the Floating Island, or the legend of the Floating Island itself for that matter, implying that the game takes place immediately after Sonic 2 when in actuality some time has passed since then, explaining how Eggman is already well-established on the island. It also leaves out Knuckles' side of the story, which involved the Master Emerald (though erroneously under the name of the "Chaos Emerald"), which the North American manual interpreted as meaning that Knuckles was the guardian of the Chaos Emeralds. The North American Sonic & Knuckles manual was also simplified, removing that part about Sonic realizing that Eggman rushed the Death Egg before launch. Additionally, when the Mushroom Hill sequence exclusive to Sonic 3 & Knuckles is dramatized, the international version implies that Knuckles' story happens simultaneously with Sonic's ("Whoever threw that bomb is in DEEP trouble."), despite evidence to the contrary.
• Dub Name Change:
  • Per the usual, Dr. Eggman to Dr. Robotnik.
  • In Sonic 3, all the Badniks have the same name in the English and Japanese versions. Sonic & Knuckles has separate names for all of them (except Eggrobo/EggRobo) in the manuals, as well as later materials such as the Japanese Sonic Jam Official Guide, which gave the Sonic 3 Badniks alternate names for some reason. Also in the Japanese strategy guide are names for all of the boss machines (like Sonic 2) except the final one, although certain English equivalents do exist in obscure publications such as the Official Sonic 3 Play Guide or the mail-in Sega of America walkthroughs (a.k.a. "hint sheets" or "cheat sheets"). While there is some overlap, each source has a different set of names for the most part.
  • The Sonic robot seen in Sky Sanctuary, originally known as Mecha Sonic in Japan, was given many official English names: "Metal Sonic" (the name of a separate character) on the back of the North American box, "Robotic Sonic" in a mail-in Sega of America walkthrough, the "Evil Sonic Robot" in Brady's Sonic & Knuckles Official Game Book, and the "Evil Sonic" in a Sonic the Comic Q Zone (mini-walkthroughs for Sega games). Eventually, the Sonic Dimensions DLC in LEGO Dimensions used his Japanese name despite the game never coming out in Japan, and gave his previous model from the 16-bit Sonic the Hedgehog 2 the name of "Robo Sonic" (one of the name changes previously given to that incarnation) to differentiate them. The Sonic 3 & Knuckles Mecha Sonic would later be known as "Mecha Sonic Mk. II" in 2021's Sonic the Hedgehog Encyclo-speed-ia.
• Dueling Player Characters: During the Hidden Palace Zone, Sonic finally gets to fight Knuckles, who had been hindering him at every available opportunity after being told by Dr. Eggman that Sonic was in fact the villain of the two. The inverse doesn't happen, as Knuckles's story takes place after Sonic's and they're no longer foes by this point.
• Dynamic Entry: This is the way Knuckles is introduced to the series. Shortly after Sonic arrives at Angel Island Zone, Knuckles bursts out of the ground and hits Sonic with enough force to knock the Chaos Emeralds out of him. Then, while Sonic is stunned, he snags the Emeralds and runs off, but not before mockingly laughing at him.
• Easy Levels, Hard Bosses:
  • When you play as Tails, the levels are incredibly easy thanks to his flight, but you'll probably run into a brick wall with some of the bosses thanks to Tails' lack of an Insta-Shield. Marble Garden Zone Act 2's Jet Drill boss is especially hard since you will be fighting it alone and cannot jump at it (the only way that Tails can damage the boss is by maneuvering to fly into it from underneath with his propellers). The difficulty is somewhat taken down in Origins, because Tails can now be Super Tails w/just the normal Emeralds (the Super Tails of original Sonic 3 and Knuckles is called Hyper Tails in Origins).
  • Knuckles' climbing and gliding let him skip large chunks of levels, and exclusive destructible walls open up drastically shorter paths. Several bosses are skipped entirely, but those that aren't tend to be made harder by his lower jump height. (e.g Knuckles needs to use the Egg Vortex's bombs to reach it, for Sonic this was simply an option) The one exception is Big Arm, which is somewhat easier as Knuckles due to his glide having the perfect range to hit it.
• Endless Game: Blue Sphere. While not truly endless, per se, 134,217,728 levels would take over a lifetime to beat.
• Epic Battle Boredom: Players can pull this off as Super/Hyper Tails by standing idly in a heated battle. He yawns while his Flickies take care of the fighting, and anyone who reaches Tails himself will suffer Collision Damage from him.
• Episodic Game: Sonic 3 by itself has the first six Zones and Sonic & Knuckles has the last eight Zones. You can "Lock-On" both cartridges together and play one big combined game, Sonic 3 & Knuckles. This was originally not the plan with the game; the entire S3&K package was supposed to be released as simply one game, but time constraints forced Sega to split the game in half so they could get half of it onto store shelves and the other half done later.
• Eternal Engine: Flying Battery Zone and Death Egg Zone are both highly technological airborne (or spaceborne in the Death Egg's case) levels controlled by Eggman. Chrome Gadget from the 2-player mode also counts.
• Every 10,000 Points: You are awarded an extra life every 50,000 points.
• Evil Knockoff: Mecha Sonic. Ironically, in the first two fights, he uses Dr. Eggman's tactics by reusing boss machines from previous games. In Knuckles's playthrough, he's The Man Behind the Man and the final boss.
• Expansion Pack: Sonic & Knuckles to Sonic 3 since the former serves as the second half for the latter.
• Faceship: The Death Egg is basically the Death Star with Eggman's face on it. While one could see what it looked like in Sonic 2's level select, it's at the end of Launch Base and the start of Sky Sanctuary that the thing is seen in clear detail.
• Fake Trap: Zig-Zagged with the enemies in Marble Garden Zone that resemble spikes. Landing on the tips won't hurt you; you'll simply bounce off as if it's a springboard. However, the enemy does pop out to shoot bullets at you, and you can still take damage from touching it if you do so from the sides. Fortunately, spin-attacking into the sides of spikes will safely reveal if they're real spikes (you'll just stop harmlessly) or a fake-spike enemy (you'll destroy it).
• Final Boss: There are three final boss machines across both games:
  • In Sonic 3 standalone, Eggman's Big Arm machine is the last boss fought, appearing right after Sonic or Tails destroy his laser airship on the platform below the Death Egg. It becomes Knuckles-exclusive in S3&K but is restored in Origins.
  • In Sonic & Knuckles, the Giant Eggman Robo awaits Sonic/Tails at the end of Death Egg Zone Act 2, after the previous Death Ball boss is destroyed. It has three phases, with the last being Eggman trying to flee with the Master Emerald while the station crumbles. If Sonic has all the Chaos/Super Emeralds after defeating this, he goes on to The Doomsday Zone, but if you're playing as Tails or do not have all the Emeralds, the game ends.
  • The last boss for Knuckles is Mecha Sonic. The first phase of the fight with him is the same as the last fight with Mecha Sonic in Sonic/Tails's Sky Sanctuary, but after defeating him here, he jets back to the Master Emerald and goes super for a second phase.
• Flame Spewer Obstacle:
  • In Flying Battery Zone, an unusual variation of flame spewer appears that shoots flames horizontally left and right. When stepped on, the flames are disabled.
  • More traditional flame spewer obstacles can be found in Launch Base Zone and Lava Reef Zone Act 2, which spis out flames at regular intervals with some spread.
• Floating Continent: The setting of the game, although it got knocked out of the sky by the Death Egg's crash landing prior to Sonic's arrival. It gets raised at the end of Sonic's story path and remains afloat throughout Knuckles' until Mecha Sonic steals the Master Emerald, which causes the island to fall back to the sea if the player fails to get the good ending.
• Foreshadowing:
  • Assuming the player is playing the full locked-on game, they're likely to have visited Hidden Palace Zone at least once before reaching it in the story proper, by hopping into the rainbow Giant Rings present from Mushroom Hill Zone on. Lava Reef Zone Act 2 uses the same music as HPZ, serving as a clue to the fact that it's related to it and immediately precedes it in the campaign.
  • There is a background mural in Hidden Palace Zone depicting Dr. Eggman stealing the Master Emerald, and Super Sonic attempting to stop him. Guess what you have to do in the true final level?
  • Similarly, the Japanese manual's story prologue briefly mentions an ancient mural depicting a legendary dragon that would bring disaster to the island. It wouldn't be until Sonic Adventure that we would learn the name and backstory of said "dragon", and see a similar mural◊.
  • The weapons used by the Giant Eggman Robo at the end of Death Egg Zone are foreshadowed by the Barrier Eggman of Flying Battery Zone Act 2 and the Heat Arms of Lava Reef Zone Act 1.
• Four-Seasons Level: Mushroom Hill Zone Act 1 is filled with green plant-life. Almost immediately after starting Act 2, everything becomes orange. Near the end of the level, the grass and trees turn a dull yellow. At the end of the level, you destroy a weather control dish and things return to being lush and green in time for the Jet Mobile Boss Battle.
• Fungus Humongous: Mushroom Hill Zone has mushrooms large enough to bounce on, use as a seesaw catapult, and parachute from.
• Game-Breaking Bug:
  • The American manual acknowledges the possibility of these and Hand Waves them as "diabolical traps" set up by Robotnik, even referring to the problem of having to reset the game or time out due to getting stuck. It particularly recommends you to activate a Star Post or enter a Special Stage at the most immediate opportunity if you are playing as Tails in IceCap Zone Act 1, due to a programming quirk that was fixed in the lock-on game where, as a result of starting at a different point of the level, Tails will die spontaneously if he reaches a vertical Wrap Around point without meeting the manual's recommended precaution.
  • If you kill Marble Garden Act 1's Tunnelbot boss off-screen by using co-op Tails, as soon as the goalpost lands, the game crashes. This only happens in standalone Sonic 3; Sonic 3 & Knuckles will force the camera to the right if you defeat the boss off-screen to prevent the crash.
  • Hyper Sonic is a virtual game-breaking machine, since the developers more than likely didn't fully test him, given that he was a last second throw-in that is normally only usable at the end of both games. But start the game back up from the first Act, and you get enough bugs to fill up three hours worth of glitch videos on YouTube. Luckily for most players, many of these are almost impossible to trigger while playing normally.
  • Tails can also trigger several game-breaking bugs (usually exploiting the fact that he doesn't clip with objects in the world if he is just off-screen), but most of these also require the player to intentionally go out of their way.
  • Some copies of standalone Sonic 3 have a real showstopper. Sometimes when you beat Hydrocity Zone Act 2's Screw Mobile as Tails, the screen remains locked in place and won't let you go over to the capsule, thus forcing the player to reset the game and play the entire level all over again.
  • The debug cheat allows for a variety of these. One common bug is to enter sprite placement mode while the player character is spinning. The graphics will glitch up momentarily, then the game will hang (if you're playing Sonic 3 alone) or reset (if locked on or playing & Knuckles by itself).
  • In the PC version, since the timer doesn't resume at Triple Score, the second Launch Base Zone Act 2 boss, you can't activate your Super State while fighting the boss (or even the third boss in Sonic 3 alone).
  • It is entirely possible for the Carnival Night Zone Act 2 Bowling Spin boss to fly off screen and never return, rendering the level unwinnable. This is not fixed in the locked-on game.
• Gameplay and Story Segregation:
  • After Angel Island Zone is set on fire, there isn't really any dramatic change to the gameplay to indicate that the Zone's on fire. No coming face-to-face with flaming walls or anything. It has basically no gameplay effect whatsoever, aside from one zip line that cuts off fairly quickly because a small section of it is burning halfway down (oh, and floating Catakiller, Jr. enemies start appearing in the flaming sections, as do spiked logs).
  • Knuckles shuts off the lights in Carnival Night Zone, but aside from raising the water level for all of 30 seconds, it seems to do nothing except show off how much of a prick he is. You turn the lights back on a little bit later.
• Gecko Ending: Without the Sonic & Knuckles add-on, Sonic 3 ends with Knuckles' plans to impede Sonic finally backfiring as he plummets to his apparent demise, the Death Egg being obliterated completely along with the rocket carrying it, and Sonic leaping into the screen to congratulate the player. While the story could be concluded here, the Sonic & Knuckles portion retcons this sequence from a decisive victory in favor of Sonic to a minor setback for the bad guys, with the Death Egg landing on the site of the Master Emerald and Knuckles going right back to harassing Sonic and Tails. The game then goes on to establish the lore behind the Emeralds, as well as give Knuckles Character Development, building up the story in favor of a more satisfying conclusion.
• Ghastly Ghost: In Sandopolis Zone Act 2, Sonic accidentally opens up a capsule filled with Hyudoros, ghostly enemies that start off harmless, but become more threatening the darker the pyramid gets, and can charge at and attack the player in their third and most powerful form. Pulling light switches temporarily turns the light back on and scares the Hyudoros away, but the Hyudoros come back when the pyramid gets darker again.
• Giggling Villain: Knuckles chuckles whenever he lays traps for Sonic and Tails. Additionally in the Sonic Origins remaster, Eggman now laughs just like he did in the previous games whenever readying his machine or when the player gets hit. As a result of this mechanic change, the Eggrobo also joins in on the giggling too.
• Glitch Entity:
  • Blue Knuckles, and his even glitchier Super State, which uses Super Sonic's palette instead of having Knuckles flash pink. For one, Blue Knuckles plays like Knuckles, has Sonic's color and lives (and the game defaults to the Sonic level routes), and uses Tails' win message when a level is completed. The character's glitchy nature renders some levels unwinnable, even with debug mode.
  • There exists a Red Sonic which plays like Sonic but uses Knuckles' life icon and color palette, and defaults to Knuckles' level routes.
• Go for the Eye: The boss of Death Egg Zone Act 1, Red Eye, is a reactor core machine. The eye is the target; you cannot damage any other part of the boss.
• Good Versus Good: Any time Sonic and Knuckles fight, as Knuckles is an Unwitting Pawn of Eggman who thinks Sonic is evil and trying to steal the Chaos Emeralds for his own selfish ends.
• Gotta Catch 'Em All: In Sonic 3, there are seven Chaos Emeralds to collect, and getting all of them lets you use the first Super State (unless you're playing as Tails). In Sonic & Knuckles, they inexplicably have to be collected again — but if Sonic 3 & Knuckles is played, the collected jewels can instead be powered up into the Super Emeralds... and collected again, for a total of 14 Emeralds. Getting the second set lets you use your Hyper Sonic, Hyper Knuckles, or Super Tails (who previously could not use the Chaos Emeralds) and get the best ending.
• Gravity Screw: Used extensively in Death Egg Zone, as well as the anti-gravity platforms in Carnival Night. Debug Mode allows you to reverse the player character's gravity at will.
• Guide Dang It!:
  • One of the most infamous examples of all time: there is one point in Carnival Night Zone Act 2 where a red-and-white cylinder is blocking your path.^note Nicknamed the Barrel of Doom. The only way to proceed is by standing on the barrel and pressing up and down on the D-Pad as the barrel wobbles. There's absolutely nothing in the game itself to suggest this. It is possible to get past it with well-timed jumps (jumping on it is the only action that gives obvious feedback) and turbo Spin Dashing under it as it recoils back up, but it is certainly not the intended solution and it's too easy to run out of time trying to pull it off. It's not unheard of for players to beat standalone Sonic & Knuckles, and the combined game as Knuckles, before ever getting to see Sonic's version of IceCap and Launch Base Zones.
  • The Death Ball boss of Death Egg Zone Act 2 drops spiked cars, and the seemingly obvious method of defeating it is to use the gravity tubes to make them fall up into it. Unwieldy as this is, it does work, which means many fans never figure out the intended method of attacking it, which is to Spin Dash into the cars while they're stuck in the ceiling.

H-P

• Hailfire Peaks:
  • Angel Island Zone is equal parts Green Hill Zone and Jungle Japes. Only after a certain point it's on fire.
  • Sandopolis Zone is a mix of Big Boo's Haunt, Temple of Doom and Shifting Sand Land.
  • Lava Reef Zone starts off as a straight volcano level, then in Act 2, the lava cools off and there's white crystals everywhere.
  • Sky Sanctuary is a castle floating among the clouds.
• Hand Wave: Hilariously done by the English Sonic 3 instruction manual in regards to certain glitches that could leave you stuck in walls and forced reset the game, which were handwaved as one of the "many diabolical traps" set up by Robotnik. Locking on the Sonic & Knuckles half will fix several of the more severe glitches, but it is still pretty easy to break wide open.
• Happy Ending Override: This game does this to the previous one, Sonic the Hedgehog 2, which ended with Sonic defeating Dr. Eggman at his Death Egg, and escaping before it explodes. The game's Golden Ending also has Sonic and Tails in possession of the Chaos Emeralds, having gathered them throughout the game. This game reveals that Eggman and the Death Egg survived as a result of crash-landing on the Floating Island, the aftermath of which was knocking the island into the sea. As part of his plan to steal the Master Emerald and use it to power the Death Egg, Eggman tricked Knuckles into thinking that Sonic was planning to steal it. The game begins with Sonic and Tails arriving at the Floating Island, only to find the place infested with Eggman's Badniks, and Knuckles stealing the Chaos Emeralds from them and proceeding to impede their progress as they fight Eggman and attempt to stop him from repairing and relaunching the Death Egg.
• Hard Levels, Easy Bosses: If you play as Sonic, you don't have Tails's flight to trivialize all the platforming, but the Insta-Shield gives you a huge attack range, and gives you the ability to bypass protections that certain bosses possess. This is slightly exaggerated for Amy in Origins Plus, as she lacks Sonic's unique shield abilities, but her hammer attacks have wider hitboxes and last longer than Sonic's Insta-Shield, letting her get more hits on bosses and more safely.
• Harmless Freezing: Subverted in IceCap Zone. The ice will do damage to the player character if they don't escape in time.
• The Heavy: Knuckles the Echidna, who makes his show-stopping entrance when he knocks the Super outta Sonic and seizes the Chaos Emeralds, who is constantly throwing every trick and trap he has at the heroes; who puts himself between Sonic and Eggman during the attempt to reach the Death Egg; who gets caught sneaking away from a special ring that leads to the Hidden Palace Zone, where he ultimately picks a fight with Sonic before an enormous prophetic mural; and who is ultimately betrayed by Eggman, leading him to make a Heel–Face Turn and help the good guys out. He even gets his own story set afterwards.
• Hero Antagonist: Knuckles genuinely believes that Eggman is a hero and allies with him against Sonic, whom he thinks wants to steal the Master Emerald. When Eggman steals the Master Emerald, Knuckles wastes no time in switching sides and assisting Sonic.
• High-Altitude Battle:
  • The Jet Drill boss of Marble Garden Zone Act 2, which is fought by having Tails fly Sonic to chase after it.
  • Big Arm, the final boss of Launch Base Zone, is fought high up in the skies, directly under the Death Egg in both Sonic 3 standalone and the Sonic Origins remaster.
• Homage: The item monitors strongly resemble Apple Macintosh computers.◊ Possibly a reference to the fact that Macs were often used to program Mega Drive games, since at the time they utilized the same Motorola 68k CPU used by the console.
• Hoist by His Own Petard: This is how many of the bosses are defeated:
  • Dr. Eggman's depth charges in Hydrocity Zone Act 2's Screw Mobile boss are the means by which you launch up to hit him. Keep in mind that the water in the boss arena is only slightly deeper than Sonic's head.
  • Bowling Spin, Carnival Night Zone Act 1's boss, has a spinning disc with spikes on the edge. The disc is supposed to destroy the floor beneath your feet, but if you hit the machine, it opens up and the disc will damage the machine upon contact.
  • Gapsule, Flying Battery Zone Act 1 boss, can be beat by making it hit itself in the head by standing on top of it and running away really quickly.
  • Barrier Eggman, Flying Battery Zone Act 2's first boss, causes the whole place to shudder and collapse by recklessly firing into the floor.
  • Guardian, the Sandopolis Zone Act 1 boss, will leap into a sand pit as hitting him does no good except throws him backward.
  • Hot Mobile, the Lava Reef Zone Act 2 boss, is destroyed when his mines slide into him.
  • Death Ball, Death Egg Zone Act 2's first boss, launches rolling spiked mines at you. However, if you reverse the gravity when the spikes are facing the machine launching them, they will damage it instead of you. The player can also speed up this process by Spin Dashing into mines whose spikes are lodged in the floor or ceiling to flip them over. If the spikes hit the Death Ball while it's flipping over then it will count as a hit in the same way as inverting gravity when they are right side up.
  • The Doomsday Zone's first part of the Final Weapon. The blue Missile Starship will shoot homing missiles at you. You are supposed to guide those homing missiles to explode into the robot's head.
• Hold the Line: You can't actually hit the Lava Reef Zone Act 2 boss, Hot Mobile, as it's covered in spikes. Instead, you just have to survive while its mines slide back into it until it blows up.
• Hopeless Boss Fight:
  • The miniboss of Angel Island Act 1 can't be defeated in its first appearance, it's coded with 256 health for the occasion, so you can't stop it setting the area on fire. You're only able to defeat it at the end of the level.
  • The EggRobo in Knuckles final stage hovers too high for him to hit, the only way to proceed is to let its claw grab you. Knuckles looks helpless, until Mecha Sonic arrives, utterly destroys the Egg Mobile and popping the animal out of EggRobo, before becoming the level's real boss fight.
• Horrible Judge of Character: Knuckles believes Eggman's claims that Sonic and Tails are the bad guys.
• Hub Level: The emerald altar in Hidden Palace Zone becomes sort of a hub Bonus Level when playing the second half of the linked game; entering a Giant Ring sends you there, where you can choose which Super Emerald you'll try to restore.
• Human Cannonball: A common level feature in Carnival Night Zone are cannons which Sonic can use to be shot to the upper parts of the level. They are also used to transport him to the following zone.
• Humongous Mecha: The final boss of Death Egg Zone, Giant Eggman Robo, is large enough to dwarf all of Eggman's previous inventions. It doesn't even fit the screen, as all the player can see from its design are the head and the upper part of its chest.
• Idle Animation:
  • As in the previous games, Sonic will look at the player and tap his foot impatiently if the player does nothing for several seconds, occasionally pointing in the direction he's currently facing. The Sonic Origins remaster has him falling asleep as well (originally a cut animation).
  • Tails will stare at the player and occasionally yawn.
  • Knuckles will start boxing impatiently.
  • Unique to Origins Plus, Amy will sway left and right on one foot. If doing nothing for several seconds, she'll clasp her hands to the side of her head and look skywards, presumably daydreaming (while still moving her right foot from the earlier animation).
• Immediate Sequel: To Sonic 2. This is perhaps subverted in the manual, as we don't know how much time passed since Eggman landed on the Floating Island and the time Sonic and Tails got there, but played straight for Sonic & Knuckles, with the locked-on version turning the final stage of 3 and the first stage of S&K into Zones 6 and 7.
• Inconsistent Spelling:
  • While it was later standardized as Eggrobo, "EggRobo" is the Badnik's earlier spelling, and also suggests that it may have been intended to be a portmanteau of "Eggman" and "Robotnik".
  • TechnoSqueek from the Sonic 3 manual was later listed as Technosqueek in the Sonic & Knuckles manual, despite it not making a proper appearance in the former game due to the zone order being rearranged relatively late in development.
• Inconveniently-Placed Conveyor Belt:
  • Inverted in Hydrocity Zone. Sonic doesn't run on conveyor belts; he hangs from them, and uses them to get to places he couldn't reach without their presence.
  • Exaggerated in Death Egg Zone. Some of the conveyor belts are moving platforms, which Sonic must take to progress, and they're designed to reverse direction each time you jump, pushing him into wall spikes or throw him into big ol' bug zappers.
• Infinity -1 Sword: Super Sonic and Super Knuckles are invincible and can move incredibly fast, but pale in comparison to the Hyper forms. In Sonic Origins, Tails can access his Super form with just the Chaos Emeralds, but can't use the Flickies that attack enemies for him, and Origins Plus features Super Amy, who cannot throw hammers like Hyper Amy can.
• Infinity +1 Sword: The Hyper forms. They're only attainable by acquiring all of the Super Emeralds, and serve as upgrades to the Super Forms. On top of the universal Super Form upgrades, they also allow the ability to breathe underwater, and grant secondary abilities unique to each character:
  • Hyper Sonic gains the Hyper Flash, an omni-directional double jump that also destroys all enemies on the screen.
  • Hyper Knuckles gains the Hyper Quake, a screen-clearing attack that triggers when Knuckles glides into a wall at high speeds.
  • Super Tails (Hyper Tails in Origins) gains Super Flickies- four orbiting Flickies that automatically attack nearby enemies, including bosses.
  • In Origins Plus Hyper Amy gains the Hammer Toss, allowing her to throw an endless volley of hammers.
• Infinite 1-Ups: Those alarm lights that trigger flying enemies in Launch Base Zone. Hold down a Spin Dash in one of those alarms, and a constant stream of enemies will fly right into you and be destroyed. The score given for the chain of hits eventually results in one life being granted every 3 seconds,^note After you destroy 12 enemies, you get 10,000 points for each enemy destroyed; you get a one-up every 50,000 points. and even if you die by time out, since it's before the first checkpoint, you can just walk back there and do it again.
• Invisible Wall: Appears in a cutscene in Carnival Night Zone Act 2, and just before the first boss battle in Launch Base Zone Act 2.
• Jungle Japes: Angel Island Zone combines Green Hill Zone with a jungle, then midway through Act 1, Eggman turns up the heat by setting the stage on fire.
• Kaizo Trap:
  • Some projectiles fired by bosses don't disappear after you beat them.
  • After beating the Hang Mobile boss of Flying Battery Zone Act 2, it's possible to land on the spiked grips of the boss and die.
  • After beating the Guardian boss of Sandopolis Zone Act 1, it's possible to die by touching the boss before he finishes sinking into the quicksand. This, like most other cases, is worsened by the fact that Super and Hyper forms instantly end when you beat the boss of any act.
  • If you beat the Hot Mobile boss of Lava Reef Zone Act 2 while in Super or Hyper form, you automatically change back to your normal form while likely standing in lava. The lava goes away several seconds later after you've had enough time to lose all of your rings, bounce, lose your mercy invincibility, and die.
  • The final fight ends with an autoscrolling section where you have to hit the bottom of Dr. Eggman's escape vehicle. Because the floor is crumbling at the same rate that the screen is scrolling, you have to stay on the right side of the screen at all times but hitting the vehicle bounces you to the left and makes you slide a lot. The problem comes when you land the final hit and the screen instantly stops scrolling at the same time that nearly all of the floor suddenly breaks at once. Surviving requires you to be super close to the right corner of the screen when you land the final hit & requires you to land the hit in exactly the right way. Logically, there should be no wrong way because hitting the vehicle should bounce you to the right.
• Kill It with Fire:
  • Midway through Angel Island Zone Act 1, a swarm of Fire Breaths firebomb the jungle.
  • At the end of Angel Island Act 2, right before the boss, you get attacked by the Flying Battery blimp, which you can't damage and instead just have to outrun its bombs (just holding right the whole time will suffice).^note Oddly enough, while only a glimpse of the underside is seen, it doesn't seem to match up with how the zone later appears in the Sonic & Knuckles portion, though the Sonic 3 manual suggests that it is Flying Battery.
  • At the end of Lava Reef Zone Act 2, Eggman uses the Death Egg's eye lasers to reignite the volcano with Sonic in the middle.
  • You can do this to enemies if you have the Flame Shield as Sonic and use its special attack, the Fireball Spin Dash.
• King Mook: The Big Icedus, faced at the end of IceCap Zone Act 1, is this to the Icedus/Star Pointers.
• Land Mine Goes "Click!": Flying Battery Zone has landmines scattered on the ground as hazards. They don't explode immediately when touched, instead blowing up shortly after contact.
• Lazy Artist:
  • The Eggrobo never gets an intro cinematic before the Angel Island Zone Act 2 boss because only Eggman has sprites for driving the Flame Machine through the woods. Similarly, Knuckles never fights the first Launch Base Zone Act 2 boss, Cannon Baller, or the Lava Reef Zone Act 2 boss, Hot Mobile, because there's no sprites of the Eggrobo piloting the Cannon Baller and Hot Mobile, respectively.
  • Knuckles fights Dr. Eggman in the Hang Mobile at the end of Flying Battery Zone Act 2 instead of Eggrobo because no front-facing sprite of Eggrobo was drawn. This is fixed in the Origins rerelease.
  • Sonic's Super and Hyper forms use palette swaps of many of the sprites of his base form. This is fixed in Origins, which gives them a full set of sprites.
  • Sonic's Super Mode comes with an Expository Hairstyle Change, Power Up Full Color Change, and Power Glows. Knuckles and Tails^note and Amy in Origins Plus just get the last one. (Downplayed with Tails, who gets four Super Flickies as well).
• Lethal Lava Land: Lava Reef Zone is one as it takes place in a underground labyrinth filled with lava.
• Let's You and Him Fight: Knuckles is manipulated by Dr. Eggman into fighting Sonic (and/or Tails, if locked on).
• Level in the Clouds: Sky Sanctuary is a construction explored from its top, which rose above the clouds. In Sonic's story, the title character must make his way across the platforms to intercept the Death Egg before it reaches orbit. In Knuckles' story, it's a Boss-Only Level where Mecha Sonic Mk II is fought; the longer it takes to defeat Mecha Sonic Mk II, more and more of the Fortress crumbles and, after 10 minutes pass, the whole place succumbs and it's Game Over. This zone returns in Sonic Generations as a Nostalgia Level.
• Levels Take Flight: Flying Battery Zone features a few segments where the player must navigate the outside portions of Dr. Eggman's blimp.
• Load-Bearing Boss:
  • Defeating Big Arm in the Sonic Origins remaster causes Eggman to crash into the hanging platform the boss fight takes place on, making it burn up and detach from the Death Egg, which then crashes on the Floating Island again.^note In the original version, regardless if both games were locked on or not, Eggman simply leaves and the platform burns up on its own.
  • The Giant Eggman Robo at the end of Death Egg Zone. Makes sense, since it not only contains the power source for the whole station, but is also so darn huge that crash landing into the superstructure would certainly do the trick.
• Logo Joke: In Sonic 3, the Sega logo remains in place as a blue ball blazes towards the camera before revealing itself to be Sonic, followed by a white flash that leads into the title screen. In Sonic & Knuckles, the Sega logo remains as the background turns into the Floating Island, rumbles and splits apart as the Death Egg crashes on the island's volcano in the background, and voila, title screen.
• Long Song, Short Scene:
  • Some of the music from the individual Sonic 3 is unused if you're playing the two games in tandem, including the fantastic miniboss music.
  • If you are playing Sonic 3 by itself and do anything that makes the music temporarily change (gain invincibility and have it wear off, start drowning and then jump out of the water, etc.) during either Hydrocity Zone boss, the song will switch to the Sonic & Knuckles mid-boss music instead of going back to the Sonic 3 version (which isn't on this mid-boss anyway; the regular boss music is used instead). The tune otherwise doesn't appear in Sonic 3 at all.
  • The battle against unpowered Mecha Sonic in Sky Sanctuary as Knuckles is the shortest battle to use the theme otherwise reserved for Sonic's Big Arms battle or the Kyodai Eggman Robo so you won't get to take in as much of it before the fight ends. The battle against Super Mecha Sonic lasts longer but it uses the theme of The Doomsday Zone instead.
  • In Sonic 3, the music that plays during cutscenes involving Knuckles plays a vocal sample 34 seconds before it loops. Problem is, you'd never hear it since the cutscenes don't last very long at all.
• The Lost Woods: Act 1 of both Angel Island and Mushroom Hill Zones take place in a lush jungle. Act 2 downplays this, as the setting is starting to show signs of devastation as a result of Eggman's exploitation.
• Magikarp Power: While Sonic and Knuckles unlock their super forms after getting 7 Emeralds, Tails doesn't unlock his until he collects all 14 Emeralds (prior to Origins). However, his Super Tails abilities (particularly the four Flickies who will attack any enemies or bosses in his vicinity) are even more of a game breaker than Hyper Sonic or Hyper Knuckles when it comes to bosses, as they let you can literally kill almost every boss just by standing in one spot (since you're invincible) and letting the birds kill the boss for you. When combined with Tails' Idle Animation, this leads to an amusing case of Epic Battle Boredom.
• Marathon Boss: The Lava Reef Zone Act 2 boss requires 14 hits to defeat as opposed to the standard 8. Coupled with the fact that you aren't control of this battle (the boss can only be damaged when the mines it's launching slide back into itself) the battle will go on for a fixed amount of time, which is pretty drawn out.
• Marathon Level:
  • The stages, compared to previous games in the series, are exceptionally long, but Carnival Zone Act 2 (for Sonic and Tails, Knuckles can choose a much shorter path) and both acts of Sandopolis Zone definitely stand out. This was possibly done to make up for the small amount of levels after the game was split into two.
  • Launch Base Zone Act 2, when playing Sonic 3 alone or the Sonic Origins remaster. The main body of the level contains an easily missed shortcut, but if you don't know your way around, you'll be forced into a massive detour. Then you have to fight three bosses, with a cutscene in between that (unlike in the locked-on game on the Genesis) continues to run down the timer. Oh, and the last boss has an annoying phase in which he goes back and forth at the top of the screen, then the bottom; during this period you can't hit him. Like every other stage, your time limit for the entirety of this is 10 minutes. This is mitigated in the Genesis version of Sonic 3 & Knuckles by cutting out the battle against Big Arm and relegating the fight to Knuckles' game.^note The Sonic 3 Complete Game Mod and Angel Island Revisited Fan Remake both have an option to restore the entire boss endurance run in full for Sonic and Tails' games.
  • Good luck finishing Death Egg Zone Act 2 (where your time at the end of the stage carries over to the big boss fight area) in under 10 minutes.
• Mineral MacGuffin: The Master Emerald and the various Chaos Emeralds. The former powers the Floating Island and keeps it, well, afloat, with the Chaos Emeralds being other major power sources that power the characters' Super and Hyper forms.
• Minus World: As Hyper Sonic, you can glitch-dash through walls into areas normally only accessible by Knuckles. A Pandora's Box of further glitches can be triggered from here.
• Mirror Boss: Knuckles, if you play as Sonic and/or Tails, though he's ridiculously easy to beat. He is pretty much the same Knuckles you can play as, with the additions of a punch attack and the ability to block by ducking. He even takes Collision Damage, though trying to walk into him will just get you punched. But you can stand in front of him and get Tails to walk into him from behind if playing as Sonic and Tails. Tails takes damage too, but he's invincible (in 2P mode). If Knuckles drops from a glide on your head, only he'll take collision damage.
• A Mischief of Mice: The Technosqueek enemy resembles a computer mouse and inhabits Flying Battery Zone. He scurries back and forth across the floor or ceiling.
• Misguided Missile: Luring homing missiles into hitting the cockpit is how you have to hurt the Missile Starship, the first part of The Doomsday Zone's Final Weapon boss.
• Mobile Factory: The Flying Battery Zone. This level features a bunch of capsules in Act 1 that contain various stuff (including Badniks).
• Motion Parallax: On top of the usual ingenious use of this camera trick across the Sonic franchise, the addition of even more layers of motion parallax allows for generating very dynamic water stages (particularly when near the surface, when the above and below backgrounds run at mismatched speeds) and smooths the two-player mode.
• Musical Spoiler: In the combined game, Lava Reef Zone Act 2 having the same theme as the regularly visited for Super Emeralds Hidden Palace Zone indicates in no uncertain terms that the latter is physically near/within the same volcano as the former, and the next Zone.
• Mutually Exclusive Power-Ups: The three shields. The player can only carry one at a time, and breaking a shield monitor with a different shield from the one you have will make the new shield replace the old one.
• Multiple Endings: Sonic has three endings depending on whenever he defeats Dr. Eggman without the Chaos Emeralds, whenever he completes The Doomsday Zone as Super Sonic or whenever he completes The Doomsday Zone as Hyper Sonic. While "defeating Eggman without the Chaos Emeralds" is the standard Downer Ending where Eggman is still shown to have the Master Emerald within the game's Stinger, the two Doomsday Zone-related endings, in contrast, are very similar, only differing in their respective Stingers - the Super Sonic ending has a Stinger which ties his story to that of Knuckles' story (where an Eggrobo can be seen on a pile of other wrecked Eggrobos, with the implication that this is the exact same Eggrobo that fights Knuckles in Eggman's stead), while the Hyper Sonic ending shows Sonic, Tails, and Knuckles all standing by the Sonic 3 & Knuckles logo.
• Never Trust a Trailer: A promotional image for Sonic & Knuckles shows Sonic and Knuckles teaming up to fight the Final Boss of Sonic 3 in Mushroom Hill. As far as anyone can tell, this was purely a mockup. Even with the Debug Mode, there's no way to replicate this scenario in-game.
• New Jack Swing: This game, alongside Sonic the Hedgehog CD, is one of the two "Classic" era Sonic games to have its soundtrack heavily influenced by the genre.
• New Powers as the Plot Demands: Tails usually tires out after a few seconds of flying. However, at the end of Marble Garden Zone Act 2, he flies for the entire Jet Drill boss fight. Afterwards, Tails heads over to the next zone without taking a break.
• Nintendo Hard: For the most part, Tails is easier to play than Sonic because he has a lot of freedom of movement, including flying and free swimming in water. Fighting the Marble Garden Zone Act 2 Jet Drill boss with just Tails, however, is immensely difficult because you can only safely hit Eggman's ship from the underside with your spinning tails while avoiding the drill and the jet exhaust, and it's nearly impossible to recollect any lost rings. Also, unlike Sonic and Knuckles, Tails cannot access a super form with just the Chaos Emeralds. Thus, he cannot access it at all in Sonic 3. Tails can only access this in Sonic 3 & Knuckles with the Super Emeralds. In Sonic Origins, this is remedied so that Tails can transform with a full set of Chaos Emeralds, with the inability to use the Super Flickies being the tradeoff. The original form can still be unlocked in the Origins version by once again snagging all the Super Emeralds, albeit now named Hyper Tails to bring it in line with Sonic and Knuckles' transformations.
• No One Should Survive That!: Par for the course with Dr. Eggman. Upon being defeated in Lava Reef Zone Act 2, his Hot Mobile is engulfed in lava, which instantly hardens.
• Non-Indicative Name:
  • Marble Garden Zone has a grasshopper Badnik named Mantis. Strangely enough, there were actual mantis Badniks in the previous game. Averted in Japan, where it's given the much more fitting name of Hopper.
  • The level select screen is labeled as "SOUND TEST" in the main menu.
  • Sonic's "Insta-Shield" move is actually a damage-dealing spin attack, and is indeed called the "Double Spin Attack" in Japan. The localizers apparently misinterpreted it due to it somewhat resembling the appearance of shield powerups.
• No-Sell: The Fire and Lightning Shields make the user immune to traps and enemies that use those elements. The Water Shield allows the user to breathe underwater and remove any danger of drowning.
• Nostalgia Level:
  • Marble Garden Zone Act 1's boss, Tunnelbot, uses a burrowing attack based on Mystic Cave Zone's Drill Eggman II boss.
  • Barrier Eggman from Flying Battery Zone is a direct Call-Back to Sonic 2's Wing Fortress Zone.
  • Hidden Palace Zone is a treat for those who had been wondering about that level that only existed as a song in the options menu of Sonic 2.
  • In Sky Sanctuary Zone, you fight a rehash of the Egg Mobile-H boss from Sonic 1's Green Hill Zone, and the Flying Eggman boss from Sonic 2's Metropolis Zone.^note Interestingly, the slight alterations of sprite proportions and game physics made both fights rather different from the originals. The Green Hill boss was originally a Warmup Boss; here he's rather harder to damage without hitting the wrecking ball on the rebound. The original Metropolis Zone boss could only be safely hit at one point in his attack pattern; here, the boss is significantly easier because he can also be damaged while he's at the top of the screen doing nothing — plus you have the Insta-Shield to pierce his shield.
• Not So Invincible After All:
  • A mild one, but in Sonic 2, Super Sonic all but insured the player was unstoppable outside the depleting ring counter and the occasional glitch. In Sonic 3, a few more scenarios are created specifically to give even the super forms a difficult time. The Doomsday Zone's Final Weapon boss basically consists of Eggman directly stalling and blindsiding Super Sonic until he'll power out and fall to his death, while both Knuckles and the Big Arm mecha are capable of harming and depowering Super Sonic upon introduction (Big Arm can't do it in the Sonic Origins remaster, however).
  • If you can glitch your way into Knuckles' section of IceCap Zone Act 1 in Sonic 3 alone (not too hard, since Act 1 allows you to use the screen wrap glitch to get on the other side of otherwise unbreakable objects) you'll find the spiny ice balls over there are capable of damaging Super Sonic since they weren't ever meant to be interacted with in the first place outside of Knuckles' trip through the area, which obviously can't happen in standalone Sonic 3.
• Obvious Rule Patch: Sonic 3 & Knuckles has this for some bugs which occurred in Sonic 3 alone. Possibly the most blatant example is a music glitch that could occur late in the first Act each of the Angel Island and IceCap Zones, which had a special case fix applied for exactly one of the four places which could trigger it.
• One Game for the Price of Two: Each half features extra features that can only be accessed in the other if you use the lock-on feature, such as playing as Knuckles in the stages for the Sonic 3 half or playing as Tails in the Sonic & Knuckles half.
• One-Steve Limit:
  • Blastoid from Hydrocity and Carnival Night and Mushmeanie from Mushroom Hill and Lava Reef shared the same name in English materials until 2021's Sonic the Hedgehog Encyclo-speed-ia used a translation of the Japanese names for the Carnival Night and Lava Reef Badniks. In Japanese materials, Sandworm shares its name with the first Caterkiller from Sonic the Hedgehog (Nal).
  • The robotic duplicate of Sonic that appears late in the game also has multiple names depending on the source - Metal Sonic according to the back of the original North American release box of Sonic & Knuckles, Mecha Sonic according to Japanese strategy guides, Archie Comics, LEGO Dimensions and recaps on the Sonic 4: Episode I websites, Robotic Sonic in a mail-in Sega of America walkthrough, the Evil Sonic Robot in Brady's Sonic & Knuckles Official Game Book, and the Evil Sonic according to the Sonic the Comic Q Zone. Later, Encyclo-speed-ia referred to it as Mecha Sonic Mk. II, indicating a relation to the Mecha Sonic robot(s) from either version of Sonic 2, though the recurring Metal Sonic from Sonic CD has no official connection.
• Optional Boss: Under normal circumstances, Knuckles never fights Carnival Night Zone Act 2's Orb of Light boss and can just pop the capsule at the end of his path to finish the level. If his climbing abilities are used to scale the fan shaft leading up to where Sonic and Tails would fight the boss, Knuckles can find the Eggrobo piloting the machine in Eggman's place and fight it as a result.
• Oxygenated Underwater Bubbles: Present throughout Hydrocity Zone, and can be released by bursting open underwater balloons in Carnival Night Zone Act 2. There's also water in Angel Island Zone, and Act 2 of both IceCap Zone and Launch Base Zone, but you have to use Debug Mode to access the bubble for those levels, as they aren't already placed.
• Oxygen Meter: Particularly funny in light of Death Egg Zone and The Doomsday Zone, as noted above. Sonic can breathe in space, but he still drowns underwater. Even Super Sonic can drown. Only Hyper Sonic has Super Not-Drowning Skills.
• Painful Pointy Pufferfish: The Pointdexters in Hydrocity Zone and the Bubbles in Marble Garden Zone are robotic pufferfish who defend themselves with their quills and can only be hit when these are gone.
• Personal Space Invader: Mega Chopper in Hydrocity Zone attaches itself to Sonic, drains the ring count at a steady pace and prevents Spin Dashes or Spin Jumps. The only reliable way to shake the robot off is by rapidly mashing the D-pad left and right. Of course, this isn't explained to the player anywhere in the manual.
• Player Nudge:
  • In Angel Island Zone Act 2, the game explains through gameplay that Giant Rings (that take you to the Special Stages) are often found in hidden paths behind walls. As Sonic and/or Tails, this stage opens◊ with a tunnel (forcing you into a Spin Dash) that ends with a straight path, shooting your characters through a breakable wall into a hidden room that contains one of many Giant Rings.
  • In the Origins remake, all of the characters now have sprites for looking up and down while on the "Barrel of Doom", giving visual feedback for the proper way to pass it.
• Poison Mushroom:
  • The power-down monitors with Eggman's face on them, also known as Eggman Marks. Opening one of these has the same effect as getting hit.
  • The versus mode in Sonic 3 has gray versions of the Speed Shoes, which slowed the player to half speed.
• Poor Communication Kills: Hidden Palace Zone has a mural showing Dr. Eggman with the Master Emerald in his hands, and Super Sonic confronting him. Evidently, Knuckles misinterpreted this as Eggman trying to save the Master Emerald, and thus treated Sonic and Tails as enemies.
• Pop-Star Composer:
  • Of a sort. Michael Jackson and his sound team were tapped to help out with the soundtrack in 1993. However, during development, they were abruptly dropped from the project. While the real reason as to why they were removed remains unknown,^note GameTrailers' "Pop Fiction" series did an investigation into this debacle: from what they found, Jackson left on his own terms because the Genesis's sound capabilities weren't to his liking and asked to remain uncredited, and Sega later unpersoned him after the child abuse claims surfaced several of Jackson's tracks made it into the final game: one of them, the original credits theme, was repurposed into Jackson's hit song "Stranger in Moscow".
  • Later ports have infamously dealt with copyright issues due to Jackson's team not receiving royalties, with one port, Sonic & Knuckles Collection for the PC, replacing the affected tracks^note Knuckles' theme, Carnival Night, Ice Cap, Launch Base, the Sonic 3 miniboss theme, the Sonic 3 credits theme, and the Competition Menu theme with alternate compositions. As it turns out, a 1993 prototype leaked in 2019 revealed that the Sonic & Knuckles Collection replacements were the original tracks, replaced with Jackson's compositions for the final game. These tracks have now supplanted the Jackson versions as of the release of Sonic Origins, with Jun Senoue, who also worked on 3 & Knuckles' soundtrack, re-arranging the prototype/PC tracks for the Retro Engine rebuild included in the collection.
• Power Floats: The Master Emerald-powered Mecha Sonic. Both of Sonic's super forms also hover above the ground when they're at full speed.
• Power-Up Letdown: Because there are no levels with water from Mushroom Hill Zone onward, the Water Shield becomes this. Even when its bouncing ability might be useful, it's completely outclassed by the Lightning Shield's Double Jump. Thankfully, the Water Shield is very rare beyond that point.
• Precursors: The former inhabitants of the Floating Island. A certain fight in the Hidden Palace Zone takes place before a mural of Super Sonic fighting the True Final Boss of the game, suggesting the presence of Seers.
• Pushy Mooks:
  • Madmoles from Mushroom Hill Zone throw mushrooms that don't damage the player but bounce them around instead, making them an indirect threat if the player bounces into something hazardous.
  • Cluckoids from Mushroom Hill Zone Act 2 will blow gusts of wind that push the player backwards.
  • Rock'n from Sandopolis Zone are giant walking blocks of rock that push the player around.
• Puzzle Boss:
  • Carnival Night Zone Act 1: You hit Bowling Spin to make it expose its weak point, but the actual damage is done when the bouncing spike platform collides with it.
  • Flying Battery Zone Act 1: You trick Gapsule into hitting itself.
  • Flying Battery Zone Act 2: A variant of Barrier Eggman from Sonic 2; you dodge it until it completely tears up the warship.
  • Sandopolis Zone Act 1: You beat the Guardian by knocking it or luring it into a quicksand pit.
  • Lava Reef Zone Act 2: You survive until Dr. Eggman's own attacks destroy his Hot Mobile.
  • Death Egg Zone Act 2: You defeat the first boss, Death Ball, by manipulating gravity to hit it with its own minibots. You can also Spin Dash at a minibot that has its spikes stuck in the floor/ceiling to catapult them at the boss.
  • The Doomsday Zone: You maneuver so the Missile Starship's own missiles hit it in the face.

Q-Z

• Quicksand Sucks: Sandopolis Zone and Desert Palace from the 2-player mode. Also, Marble Garden Zone features a tar-like substance that behaves the same way as the other examples of quicksand.
• Rearrange the Song:
  • One of the greatest discussions among fans concerning this game is trying to figure out which Sonic 3 songs are re-purposed Michael Jackson songs. One of the rearranged songs that wasn't made by Jackson is IceCap Zone's theme, which is actually a slightly remixed version of a then-unreleased song from the music group The Jetzons called "Hard Times"; the band included Brad Buxer, who was a songwriter for Jackson and is credited among the game's composers.
  • In most Zones, the music of the second act is a rearrangement of that Zone's first act.
• Race Against the Clock: Sandopolis Zone Act 2 is this in spades. You have to race against dimming lights, slowly closing doors, rising sand sections, and the 10 minute time limit. Even the Egg Golem boss has a limited time to be defeated before he crushes you.
• Recurring Riff: The "Level Clear" music from this game has been reused by many other Sonic games, and even shows up as Sonic's victory music in Super Smash Bros. Brawl.
• Recycled Soundtrack:
  • The "Blue Spheres" theme was originally written by Yoshiaki Kashima for the cancelled arcade game SegaSonic Bros. Since Kashima also wrote the sound driver for Sonic 3 & Knuckles, he was able to reuse the track.
  • The prototype tracks that were cut from the original Genesis game ended up getting rearranged twice to be used in place of the final Genesis tracks: first in Sonic & Knuckles Collection, a PC port of the game, then again by Jun Senoue for the Retro Engine version included in Sonic Origins (though it's theorized that these originate from an even earlier prototype).
• Remilitarized Zone: Launch Base Zone and Flying Battery Zone take place in Eggman's base as he prepares to launch the Death Egg and a warship, respectively.
• Replaced the Theme Tune: If you have Sonic 3 hooked up to the Sonic & Knuckles cart, its title theme is replaced by the one from Sonic & Knuckles. Same goes for some of the music in the game itself (1-up theme, mini-boss theme, invincibility theme, Knuckles' theme, and the credits theme).
• Rhino Rampage: The Rhinobot enemy is a robotic rhino who inhabits Angel Island Zone. He stands on one wheel, moving back and forth across flat terrain, but will charge at the player if they get close to him.
• Ring-Out Boss: The Sandopolis Zone Act 1 boss, Guardian, which you have to lure into a quicksand pool.
• Rivals Team Up: Sonic and Knuckles pull this after the latter realizes that he was tricked by Dr. Eggman.
• Rule of Cool: IceCap for Sonic begins with a snowboarding sequence that can earn him up to 50 rings before the stage even starts. Why? Because Sonic is the coolest mascot in gaming!^note In reality the original concept for Sonic 3 had Flying Battery precede IceCap, during which Sonic would bust through a door on his way out of the zone, which in turn would become the "snowboard" at the start of the following zone. When this was changed due to Sonic & Knuckles getting Flying Battery, the snowboard section just became a disconnected-but-awesome showcase for the blue guy's extreme sports skills.
• Rule of Symbolism: After Knuckles is tricked into villainy for all of Sonic 3 and Sonic's story in Sonic & Knuckles, requiring Sonic to be the hero, his own story lets him redeem himself and pay his debts in full by defending the floating island from another attack. The fact that the Final Boss of his story is an Evil Knockoff of Super Sonic lets him settle that score in spirit, too.
• Sampling: The standalone Sonic 3 soundtrack makes heavy use of sampling vocals and sound effects from popular songs, and, as noted in Pop-Star Composer, reusing melodies from some of Michael Jackson and Brad Buxer's discographies.
• Sand Worm: A badnik with this very name shows up in Sandopolis Zone and ambushes Sonic over sand pits.
• Scary Scorpions: The Skorp enemy from Sandopolis Zone have a far-reaching tail attack.
• Scenery Porn: Beautiful pixel art, and impressive parallax scrolling on the backgrounds. There are a lot of little cosmetic details in the graphics. The water levels in Hydrocity Zone Act 1 and Launch Base Zone Act 2 match the surface and have different backgrounds below them, leading to a great effect.
• Schmuck Bait: The Eggman monitors. Hitting one will either cause you to lose your shield, lose all of your rings, or die if you don't have any. The monitors are a non-issue for the Super/Hyper forms.
• Scoring Points: Complete an act with the clock on 9:59 (one second before a Time Over) and you are awarded 100,000 points, enough for two extra lives. Not easy as it is at that time you must land the critical hit on whatever boss you're fighting. It's easy to do this with Knuckles in Carnival Night Zone Act 2, as he doesn't fight a boss.^note Unless you know how to access it. Just stand in front of the capsule until 9:58 or so and then jump and break the capsule. Requires patience.
• Secret Level: The Doomsday Zone, which is only accessible if you beat Death Egg Zone as Sonic (with or without Tails, who gets left behind either way), with a full set of Emeralds (either Chaos or Super will work), and is just an extended fight with Dr. Eggman's final mecha. This level is inaccessible when not playing as Sonic.
• Segmented Serpent: Flying enemies in Angel Island Zone, flying enemies in Mushroom Hill Zone, Sand Worms in Sandopolis Zone, and yet more flying enemies in Lava Reef Zone. Hitting them anywhere besides the head will injure you.
• Sentry Gun: A few can be seen in Lava Reef Zone Act 1 guarding doors. Destroy one, and the door below that gun will open.
• Sequence Breaking:
  • It's possible for Tails to skip a few midbosses simply by flying past the area where you fight them. For example, the Big Icedus boss of IceCap Zone Act 1 can be skipped if you're using Tails and fly above the midboss area. This causes a few glitches in Act 2, though. The Mecha Sonic fights in Sky Sanctuary Zone can also be skipped this way.
  • You can glitch dash through certain walls as Hyper Sonic, allowing you to reach areas normally reserved for Knuckles. Be warned, as you may get stuck and encounter glitches.
  • You can glitch dash through the Flying Battery Zone Act 2 boss so you end up on the other side of the barrier looking at Eggman. You can go almost to the top of the level but the clouds and boxes are glitched.
• Sequential Boss:
  • The Insta-Freeze boss of IceCap Zone Act 2, Eggman/Eggrobo with a frost blower and a platform below it. Eggrobo will raise and lower the platform, while Eggman will keep the platform down. After 6 hits, the platform breaks off and the ice reserve tank on Eggman's ship busts open.^note You can get frozen from touching that part of his Eggmobile when the tank starts leaking. Two more hits and this boss is finished.
  • The boss of Launch Base Zone Act 2 is a three-parter in both Sonic 3 alone and the Sonic Origins remaster, a two-parter on the locked-on game. For Sonic/Tails, you first have to deal with Eggman's Cannon Baller machine on land, then after Sonic (joined by Tails in Origins) rides the spare Eggmobile to the Death Egg's platform, Eggman returns in a laser Triple Score airship. In the locked-on game, destroying this airship ends the Act, but in Sonic 3 alone and Origins, you get those versions' "Big Arm" Final Boss after the Triple Score is destroyed. Knuckles, when he reaches his Act 2 boss area, goes straight to the Triple Score and then has to deal with "Big Arm" before an end-of-zone capsule appears for him to bust open to end the stage.
  • The boss of Death Egg Zone Act 1 is Red Eye, a station core rotating exploding balls. After delivering 6 hits, the central machine with the eye comes out of the core and produces two spinning platforms, and hitting it now causes it to fire a laser across the floor. 6 more hits are required to destroy it.
  • The last boss scenarios in Sonic & Knuckles are both sequential:
    • For Sonic & Tails, the player first has to deal with another robot controlled by Eggman that spits out rolling spikes. After destroying this thing, Sonic/Tails chase Eggman into his Death Egg Robot, and the first phase of this is a Background Boss where the player has to destroy the individual fingers, then hit the nose of the robot to reveal the core and Master Emerald and hit that, and then hit Eggman's escaping Eggmobile with the Emerald in tow while the walkway is crumbling behind you. If Sonic has all the Emeralds, he then goes on to the Zone that features the True Final Boss, which also has several phases. The first phase requires Sonic to lead Eggman's missiles back into his craft's face, and then he has to catch up with the craft and smack it.
    • For Knuckles, it's two phases of Mecha Sonic. The first phase is the same as the fight in Sky Sanctuary when playing as Sonic/Tails, but then Mecha Sonic starts charging himself up on the Master Emerald and goes Super. When he fires energy blasts, he comes down to recharge, and that's when the player can hit him. When Mecha Sonic is down to two hits, he limps in the air and fires a spread-shot of rings, and ducks down every one in a while. Hitting him here will finish him off.
• Shifting Sand Land: Sandopolis Zone and Desert Palace, as the names imply, take place in a desert.
• Shoo Out the Clowns:
  • In the standalone Sonic 3, after the first Cannon Baller boss fight in Launch Base Zone Act 2, Sonic flies an Egg-O-Matic to the final arena. Tails stays behind and doesn't join Sonic for the two final battles, and Knuckles gets knocked off into the water on the way there. Once Sonic gets off the hovercraft, it's just him and Eggman.
  • In Sonic 3 & Knuckles, when the game is played as Sonic and/or Tails, Knuckles stays behind to recover from being electrocuted at the beginning of Sky Sanctuary Zone and only reappears during the end credits after this. Later, if the game is played as both Sonic and Tails, the latter disappears once Sonic flies off to face Dr. Eggman in The Doomsday Zone.
• Shout-Out:
  • The final boss and mural seems to be taken from Nausicaä of the Valley of the Wind, while elements of the Floating Island itself, Hydrocity, Hidden Palace, and Sky Sanctuary have similarities to elements of Castle in the Sky.
  • The Death Egg is also an obvious reference to the Death Star from Star Wars, the only known difference in the appearance being Eggman's face built onto it. While it had a level select icon in Sonic 2, it was difficult to make the resemblance out. Both 3 and & Knuckles show it in full unobstructed detail, making the shout out even more blatant than before.
  • According to Word of God, the design of the Special Stages being on a small spherical planet that you constantly loop is based on King Kai's planet from Dragon Ball Z.
• Sky Heist: In Sonic's storyline, after Sonic defeats Knuckles in Hidden Palace Zone, Knuckles rushes over to the Master Emerald Shrine to discover that Dr. Eggman had tricked him into thinking that Sonic is his enemy to distract him so that he could steal the Master Emerald and use it to power the Death Egg. Dr. Eggman uses the claw from his Eggmobile to snatch the Master Emerald so he can fly away with it. Knuckles tries to stop him by latching onto the Master Emerald, but Dr. Eggman electrocutes Knuckles to keep him from taking it back.
• Slasher Smile: Knuckles when he controls the lever that sends Sonic to the upper part of Mushroom Hill Zone's second act.
• Slippy-Slidey Ice World: Subverted. IceCap Zone is the frozen region of the Floating Island. It has frozen peaks Sonic snowboards down from and a cave complex filled with spiky icicles. However, the surface is not slippery at all.
• Smart Bomb:
  • When Lightning Shield meets water the screen will flash, the shield will be lost and all enemies on screen are destroyed.
  • When Hyper Sonic does a double jump or Hyper Knuckles hits the wall, the screen will flash and all enemies are instantly destroyed.
• Smashing Hallway Traps of Doom: IceCap Zone and Sandopolis Zone have the most of them.
• Snap Back: While there are numerous environmental cues that indicate Knuckles' story takes place after Sonic's^note The ocean is no longer visible in Angel Island Zone, the Hyudoro ghosts of Sandopolis Zone have already been released, several areas have had the major events of Sonic's story undone.
  • The jungle of Angel Island Zone is lush once again despite being razed with fire bombers in Sonic's story.
  • The hidden pyramid of Sandopolis Zone returns to being buried in the sand between Sonic's visit and Knuckles's visit.
• Solid Clouds: In Sky Sanctuary, solid clouds serve as trampolines in order to reach higher areas. This is carried over into its appearance in Sonic Generations.
• Songs in the Key of Panic: In The Doomsday Zone, the music speeds up if you dip below eleven rings.
• Space Zone: Death Egg Zone takes place in a space station, while The Doomsday Zone has Sonic flying through space in his Super or Hyper form.
• Spell My Name with a "The": Fans often shorten it to Doomsday Zone, but the location of Sonic's True Final Boss is actually The Doomsday Zone, which is sometimes shortened to The Doomsday in-game.
• Spikes of Doom: One enemy in Marble Garden Zone subverts this; it fires projectiles at you, but hitting the tips of the spikes merely bounces you off without any damage. This is double subverted, as this being an enemy, you will still take damage by running into the side of the spikes, something that doesn't happen with real spikes.
• Stationary Boss:
  • The Cannon Baller at the end of Launch Base Zone Act 2 for Sonic and Tails has Eggman in a stationary cockpit on top of a pillar. He will not move, and you have to use the ball hatch under the machine to reach him.
  • This applies to the first phase of the fight with the Death Egg Zone Act 1 boss, Red Eye, as it is encased in a turbine and only the eye moves. After this phase ends, it emerges from the turbine and starts floating around the room.
• Stalactite Spite: There are stalactites and icicles in Lava Reef Zone and IceCap Zone, respectively.
• Stalked by the Bell: In Sandopolis Zone Act 2, ghosts start to appear as lights in the level go out, and will start attacking unless the player continues to switch new lights on.
• Steel Drums and Sunshine: The music for Angel Island Zone has a steel drum playing part of the melody (or rather, the best approximation of a steel drum sound that the Genesis sound chip can synthesize) befitting a tropical island jungle stage. It's slightly less fitting for the second half, where the jungle gets napalmed and becomes a raging forest fire.
• The Stinger: Like in the first game, and the 2013 remake of the second game, after the credits roll a small scene plays:
  • In vanilla Sonic 3, failure to collect all Chaos Emeralds shows Dr. Eggman and Knuckles in possession of them, laughing. Likewise, failure in Sonic & Knuckles or the full game has either Eggman or Mecha Sonic claiming the Master Emerald.
  • Collecting all Chaos Emeralds as Sonic or Tails in Sonic & Knuckles but not starting the Super Emeralds quest in the full game shows the last Eggrobo awakening, which links Sonic and Knuckles' stories.
  • Collecting all Emeralds in Sonic 3, or upgrading them in 3 & Knuckles results in the heroes posing by the game's logo.
• Stop Hitting Yourself: This is how Gapsule, the boss of Flying Battery Zone Act 1, has to be beaten. You need to make its spikeball arms hit itself by standing on it, then running away at the last second when they attack.
• Story-Driven Invulnerability: At several points, Eggman shows up outside of a boss fight but cannot be destroyed.^note at least, not without exploiting some game-breaking bugs that allow you to land 256 hits on him. The most notable instance is during his theft of the Master Emerald.
• Super Mode:
  • In addition to the usual Super Sonic, it's also possible to play as Super Knuckles. And if you collect all 14 Emeralds you can become Hyper Sonic, Hyper Knuckles, or Super Tails^note In Sonic Origins, Tails becomes Super Tails with just the Chaos Emeralds, and the original Super Tails form achieved with the Super Emeralds has been rechristened to Hyper Tails. Amy, added in the Origins Plus DLC, also gets a Super and Hyper Form.
  • Mecha Sonic gains one of these at the end of Knuckles' story as the final boss, though in this case he uses the Master Emerald to power his super form, something the Master Emerald has only done here and wouldn't be doing again until Sonic Chronicles.
• Super Not-Drowning Skills:
  • Bestowed by a Water Shield when you go underwater.
  • The Hyper forms of Sonic and Knuckles can breathe underwater without the Water Shield, but by the time it becomes possible to get these forms, you've already passed the last level with water in it. Breathing underwater is thus only relevant if you're replaying any of the Zones with water on a save file.
• Tactical Suicide Boss:
  • The Act 1 bosses of Flying Battery Zone (Gapsule) and Sandopolis Zone (Guardian) have to be tricked into killing themselves - the former by hitting its own head while Sonic stands above it, the latter by being lured into a sand pit.
  • The Barrier Eggman mini-boss in Flying Battery Zone Act 2 merely involves dodging Eggman's laser. After enough shots, Eggman will have caused too much damage to his own warship, causing it to start falling apart. Likewise, the actual end boss of the stage can't be touched normally but swings itself above the platform the characters stand on for...reasons.
  • The Lava Reef Zone Act 2 Hot Mobile boss. The spikeballs it sends out eventually come back down the slope and hit itself. It's otherwise completely immune to any attacks, including Super/Hyper forms.
• Temple of Doom: Hydrocity Zone, Marble Garden Zone, Sandopolis Zone Act 2 and Hidden Palace Zone all take place inside a temple.
• Temporary Platform: Some are these present in various zones.
• Theme Music Power-Up: The invincibility music for both Sonic 3 and Sonic & Knuckles are versions of their title screen themes.
• This Is a Drill: All of the bosses from Marble Garden Zone attack with drills.
• This Is Something He's Got to Do Himself: In the standalone Sonic 3, if playing as Sonic and Tails, Sonic will abandon Tails once he boards the single-seater to the Death Egg. This is averted in Sonic 3 & Knuckles, where Tails catches up because he remembered to fly. The Sonic Origins version averts it harder by having Tails enter the vehicle with Sonic.
• Timed Mission:
  • Every level has a time limit of 10 minutes, which is usually far more than enough. Act 2 of Carnival Night, Sandopolis and Death Egg Zones often come close, though.
  • In The Doomsday Zone, a second time limit is imposed by Sonic's Super State slowly draining the rings in his possession; run out, and you fall to your death. This is particularly dangerous when you reach the first boss battle as there are no rings at all in this section. You need to score all the necessary hits and wait for the ship to fall offscreen and explode before you can enter the next phase where there are rings again. Luckily during the final phase the ring patterns loop endlessly^note Although due to the rate at which Super Sonic burns rings the only way to get a positive balance is to pick up the six-ring clusters that appear once per loop — the three ring clusters only provide enough rings to make it to the next cluster, meaning missing a single cluster will result in a negative gain.
  • Used to great effect in Knuckles's version of Sky Sanctuary Zone. The Floating Island is slowly sinking in the background and will drop off the screen at the 10 minute mark.
• Totally Radical: The Monkey Dude Badnik in Angel Island Zone, an obvious update of the similar Ai Ai/Coconuts Badnik from Sonic 2.
• Tropical Island Adventure: The whole game takes place on a tropical island, though the first Zone, Angel Island Zone, is particularly tropical.
• True Final Boss: The Doomsday Zone. To unlock this, Sonic must all collect all the Emeralds prior to going to Hidden Palace Zone (although you can enter The Doomsday Zone if you just have the regular Chaos Emeralds, the Super Emeralds being optional if you're playing locked-on). This would be the first example of a Super Sonic-only final boss in the series, a trend several future Sonic games would follow (though in some of those instances the battle was just a part of the story as opposed to a secret stage that had special criteria to unlock).
• Tube Travel: Several zones have tubes which Sonic can travel through by entering one end, zooming through a series of tubes then coming out of the other.
• Underground Level: Endless Mine from 2-player mode. For 1-player, you have Hydrocity, IceCap (but not entirely), Lava Reef, and Hidden Palace.
• Updated Re-release:
  • The And Knuckles part changed the sub-boss music and Knuckles' theme that were originally in 3. This later on passed on to the other re-releases.
  • The PC release changed the songs of Carnival Night, Ice Cap, and Launch Base, as well as the credits music and the competition mode select music, to its original track before the involvement of Michael Jackson and Brad Buxer due to licensing issues.
  • Origins changed and added a couple of things:
    • If playing the game in Anniversary mode, the game is now in 16:9 widescreen, on par with the other Retro Engine rebuilds.
    • The Special Stages' framerate is more consistently smooth.
    • All of the Competition Mode stages now display at the same size as the actual game's Zones. The physics and controls, including the lack of Sonic's Insta-Shield and Knuckles' gliding and climbing, are still identical to the original game, however.
    • Level select is accessed using the same method as standalone Sonic 3, but the code can now be input any time before pressing start, making it much easier to access compared to Sonic 3's incredibly tight frame window. The level select menu itself has also been slightly revamped, and if Debug Mode is active, it allows the player to play any Zone (character-specific and boss-only sections included), Competition Mode level, Bonus Stage, Special Stage, and either regular Blue Spheres or New Blue Spheres as any character, notably finally allowing Sonic and/or Tails to properly play Knuckles' Sky Sanctuary act and vice-versa.
    • The Big Arm boss during Sonic's (or Tails') quest in Launch Base Zone, previously missing when using the lock-on technology or playing the other re-releases, returns. Additionally, after defeat, a new(-ish) in-game cutscene plays, depicting Eggman fleeing (using previously-cut sprites) as the Death Egg crash-lands back onto Angel Island (partially depicted using elements of the title sequence of Sonic & Knuckles).
    • Sonic now has the Drop Dash, ported from Sonic Mania.
    • Tails can now go Super with just the Chaos Emeralds, but lacks his Flickies. Getting the Super Emeralds upgrades him to Hyper Tails, which is equivalent to the old Super Tails, complete with Flickies.
    • There are also a number of minor adjustments here and there, like additional, sometimes previously-cut sprites and animations for all of the main cast members (most notably Super/Hyper Sonic, who doesn't share any of regular Sonic's sprites any more), Eggrobo properly replacing Eggman during Knuckles' Hang Mobile fight in Flying Battery, and a unique intro cinematic for a solo Tails playthrough depicting him landing the Tornado on Angel Island.
    • The Origins Plus DLC adds perhaps the biggest change of the bunch: The ability to play as Amy Rose. For the most part, Amy is a Moveset Clone of Sonic, having moves that act like Sonic's Insta-shield and Drop Dash (though Amy's version of the Insta-shield, which has her spin her hammer has a much larger and longer-lasting hitbox than Sonic's does and can be used even while transformed or using a shield), and unlike in any past appearance, she can actually turn Super and Hyper. Hyper Amy has a unique hammer throw attack that may be inspired by a similar move Amy can perform in Sonic the Fighters, though this is far less useful than the abilities of the other three Hyper forms, making it Awesome, but Impractical in comparison (Amy doesn't really need a projectile attack when she's already invulnerable from turning Hyper to begin with, and it's not automatic like Super/Hyper Tails' flickies).
• Underwater Ruins: Hydrocity Zone takes place inside of one.
• Under the Sea: Hydrocity of course, but the Sonic 3 half has noticeably the most water in any Sonic game, with Marble Garden being the only Zone (of six) without it. The second acts of Carnival Night (only as Sonic and Tails) and Launch Base have enough water to double as secondary water levels to Hydrocity's main one. There are fewer water segments when playing as Knuckles and the Sonic & Knuckles half has none at all — though you can call Sandopolis a water level in disguise. Despite being a desert, it has all the markings of a Sonic water level.
• Unintentionally Unwinnable:
  • In Hydrocity Zone Act 2, it's fairly easy (though fixed in the locked-on game) to go past the boss and right to the capsule without doing the boss fight. Unfortunately, for some reason, this prevents the level transition cutscene from playing, and while the timer keeps ticking up, you won't die when it hits 10 minutes. The only way out is to reset.
  • When playing as Sonic with Tails tagging along, it's possible to glitch Tails off-screen so he doesn't return. Doing so in Marble Garden Zone makes it impossible to fight the boss.
  • Knuckles isn't supposed to get into Death Egg Zone at all, but if you get him there via level select, you'll find that the Act 1 Red Eye boss is impossible to defeat because the core is too high for his lower jumping height.
• Unskilled, but Strong: Tails isn't as efficient with the emeralds as Sonic and Knuckles, since he needs the Super Emeralds for his Super Tails form (as opposed to Sonic and Knuckles having Hyper forms). That said, it's undoubtedly the most powerful one, since, along with the usual perks, the Super Flickies he summons make bosses even easier.
• Useless Item: The Water Shield in Sonic & Knuckes alone or past Launch Base in the complete game due to every Zone lacking water negating its primary function (making characters immune to drowning). Not entirely useless (you still get one hit to protect your rings) but very underwhelming compared to the Lightning or Flame Shields. For Sonic, he can still make use of the bubble bounce but the Lightning's Double Jump is more practical and you get the added bonus of ring attraction/electrical immunity and for Tails and Knuckles wearing this shield in those stages is no better than the basic shield from the previous games (if you don't count bullet repulsion, which every shield grants in this game).
• Video Game Caring Potential: Many fans have commented that they did not have the heart to leave the injured Knuckles on his own in Sky Sanctuary Zone. Perhaps because of this, if you duck near him in just the right spot, he'll make a gesture that quite clearly means "I'll be fine, Go On Without Me".
• Walk, Don't Swim: Tails can swim. Knuckles can glide in the water. Sonic sinks like a rock.
• Walk on Water: You can run across the surface in Hydrocity. In Sonic's main path of Angel Island Zone Act 2, you get a brief demonstration of this ability, which is something you couldn't do in the previous game.
• Water-Geyser Volley: In Hydrocity Zone, a few areas have your characters ride the current through underwater tunnels before going vertical, with the water and your character bursting through the floor and up into the air. The second act of the Zone ends with water spouts of the same variety forming beneath the characters and blasting them into Marble Garden Zone.
• Waterfront Boss Battle: Both Acts of the Hydrocity Zone end with a battle where Sonic is in the water, but the boss is above it. For Act 1, the water is deep enough to drown in, and the Big Shaker boss stirs up the water to knock you off your feet. For Act 2, the water is waist-deep, and Eggman uses it to try and pull you into his Screw Mobile's whirling propeller.
• Weaksauce Weakness: Flame Shields let you run over molten magma and Lightning Shields make you a ring magnet and immune to electricity, but both are immediately cancelled if you touch water, though the latter also acts as a Smart Bomb when this happens. Annoying in the Sonic the Hedgehog 3 portion, with water in five of its six Zones, but not once you reach the Sonic & Knuckles levels which have no water sections at all. Strangely, being in Super or Hyper form will allow the Lightning Shield and Flame Shield to remain, but you'd only notice this with the Lightning Shield's ability to attract rings. The shields also disappear once you lose the form.
• Weaponized Exhaust: If the boss uses a rocket to fly, it can use that rocket to hurt you. Luckily, though, the developers had foresight; if you have a Flame Shield, you're unaffected by the exhaust, giving you a great angle to attack from.
• Weapons of Their Trade: Hey Ho, the boss of Mushroom Hill Zone Act 1, chops blocks of wood at the player with his axe.
• Weather-Control Machine: Featured in Mushroom Hill Zone Act 2.
• What the Hell, Player?: In Competition mode, if one player jumps the starting line before the countdown reaches "GO!", a buzzer plays, "FAULT" appears on their side of the screen, and both players are put back before the line to wait out the countdown again.
• What Happened to the Mouse?: Midway through Angel Island Zone Act 1, a Fire Breath appears, and the miniboss music starts playing. While you can attack the boss, it doesn't fight back and instead just launches napalm rockets in the air, while in the background you can see dozens of identical robots doing the same. It then flies offscreen before you can do anything, and, while you fight another one as the actual Act 1 boss (or maybe the same one, who knows?) what happened to all the other ones you saw earlier is never explained.
• Wide Eyes and Shrunken Irises: Many of the Badniks have this kind of look.
• A Winner Is You: Played straight by the stand-alone Sonic 3, which has a very abrupt and anticlimactic ending that was clearly thrown together at the last minute in order to get the game out in time. Averted by Sonic & Knuckles and the combined Sonic 3 & Knuckles, which have a variety of different endings depending on how well you did, even if none of them are quite as iconic as that of the previous game.
• Word Salad Title: Flying Battery Zone is often mistaken for this. However, one definition of battery is a group of guns that fire simultaneously. Presumably that's what the name refers to.
• The Worf Effect: Knuckles' introduction has him knocking Sonic out of his invincible Super Sonic form before swiping the Chaos Emeralds.
• Wrap Around: A few areas in IceCap Zone and Sandopolis Zone tend to loop when not exited from them properly. With the "Hyper Sonic" in Sonic 3 cheat, you can wrap around back to the first Act of a Zone, resulting in messed-up graphics and other glitches. Though if you want to be pedantic, this isn't technically a Wrap Around at all, but the "loopback", which is the level geometry repeating ad infinitum to prevent a crash if you somehow get there. A few levels are taller than the engine can handle. The developers got around this by making the level wrap vertically and making them intersect with themselves a certain way. On these levels, you can perform a vertical Wrap Around just by ducking until the camera goes as low as possible, then quickly jumping off the top.^note This works because on vertical wrapping levels, the engine tracks the player's position relative to the camera, rather than map coordinate 0-0 as it does on fixed stages, so jumping off the top results in suddenly being a massive distance below the camera, several "laps" of the stage down. Results vary from getting stuck in the wall to skipping large segments of the stage.
• X-Ray Sparks: When Knuckles gets electrified.
• Yodel Land: The Multiplayer race stage Azure Lake Zone takes place at a pristine lakeside meadow surrounded by mountains.
• Your Size May Vary: The size of the Death Egg seems to change depending on the zone. In Launch Base Zone, it's small enough to fit in the harbor, while in Lava Reef Zone, it's just barely big enough to cover the mouth of the volcano without falling in. When you actually go inside it in Death Egg Zone Act 1, it seems as large as a small city.

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