Sonic the Hedgehog 3 & Knuckles/Bugs

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This article needs cleanup. This article needs to be edited to conform to a higher standard of article quality. Specifically, issues with this article are: Many of these bugs are too vague to understand properly. Bugs that appear in vanilla Sonic 3 should live in Sonic the Hedgehog 3/Bugs. Bugs that appear in Sonic & Knuckles should live in Sonic & Knuckles/Bugs. This list should only feature bugs that exist in the locked-on game (e.g. Knuckles in Sonic 3 levels, Tails in Sonic & Knuckles levels, Hyper Sonic etc.) After the article has been cleaned up, you may remove this message. See How to Edit a Page for help.

This is a list of bugs, glitches, etc. that have been found in the locked-on game Sonic 3 & Knuckles.

General bugs

Mid-boss music for main boss fight

The game will occasionally play the mid boss music for the main boss.

Not fixed in any version.

No Music for Act 2

At the end of the score tally, the music can sometimes simply disappear if you get a specific amount of points. This because the jingle for getting an extra life interrupts the music for the next Act to start.

Not fixed in any version.

Mid-boss monitors

A couple of interesting things can be done with the monitors that show up after a boss fight:

• If you destroy a Super Ring monitor right before the score tally comes up, your ring counter will show the right amount of rings, but you will only gain the amount of points of the rings you had before destroying it.
• If you destroy a Water Shield monitor at the right time, it will cancel out the music for the next Act.
• As they bounce out of the ground, if you were to get under them they can either crush you or push you into the ground.

Not fixed in any version.

Slope Glitch

There are several circumstances in which Sonic or any other character can achieve a sort of 'zero gravity' mode whereby he can walk in the air, without fallling (as he should) until he jumps. He keeps walking at the angle of whichever platform he was on when the state was triggered and will not be able to walk at another angle without jumping again. With this mode, Sonic can pass through any floor or wall and reach areas that are normally unreachable without debug as long as you can find an enough angled floor to build momentum from.

Circumstances where Sonic can achieve this state include:

• In Carnival Night Zone, if Tails puts Sonic into the cannon, Tails will enter the cannon whereas Sonic will not. If Sonic Spin Dashes on the cannon and releases it at the right time, he'll enter the zero-gravity state.
• In IceCap Zone, if Tails breaks an ice cube while Sonic is standing on it or if he touches the ice that is broken by the platform in the first infinite tunnel.
• Launch Base Zone; and
• In Flying Battery zone, if Tails brings Sonic to one of the hangers or if a character stands next to the spring on the mid-boss as it is dying.

Explanation: This glitch happens because the plus $08 flag at the RAM address $B02A (whose purpose is to stop Sonic from falling through objects) is not reset to normal after Sonic leaves the object on which he is standing. When Sonic stands on another object, destroys an enemy from above, or enters a Bonus/Special Stage, the flag is properly reset to normal and the glitch thereby stops.

Not fixed in any version.

Horizontal Underflow/Level Wrapping

Character position is stored with hex values and while the game has "physical" restrictions to stop you from under- or overflowing the position value, this can be overcome by having enough speed when running towards one of the stage endpoints to avoid the hit-detection.

Depending on the level, there's a large or small "loopback area" which basically is a glitchy repeat of the level. There are no objects placed here, but triggers based on the "camera" position still work.

When doing a wrap, the "camera" will rush towards the other end of the Act in order to try and catch your character. If a "camera" triggered event that locks the screen occurs, such as a boss fight, your character will teleport to the nearest edge, even if it's right inside a wall. If your vertical position is higher than the locked position, the character will just fall back into the map and if it's lower, the game will behave as if you fell into a bottomless pit and you'll die.

Not fixed in any version.

Camera manipulation

Hey Eggman, what are you looking at?

There's a couple of ways to manipulate the camera. This can be abused since objects are only loaded when they're on-screen. Different objects can be loaded at different distances from the camera however. Some examples include springs and spiked crushers in Lava Reef that are loaded approximately 1.1-1.4 screen-lengths away (which makes sense as springs should work even if you're running or rolling so fast that you go slightly ahead of the camera and the crushers because their moving cycle timer only start when they're loaded) and general obstacles like rocks and spikes which are unloaded as soon as they're offscreen.

The methods most commonly used are:

• Crouching and jumping above the screen in stages that loop vertically. These include Marble Garden 1, IceCap 1 and Sandopolis 2. Interestingly enough it can also be used to manipulate the vertical screen locks in Sky Sanctuary and go from the bottom of the stage to the top of the stage instantly as the stage technically loops at one point in order to fit the height of it.
• Spindashing. If a character comes with a high velocity towards a wall or an object, comes to a quick stop and then quickly spindashes; the screen will be displaced proportionately to how fast the character was travelling previously and how quickly he stopped and later spindashed. If done correctly, most solid objects that blocks the path of a character can be bypassed by doing this including the ones blocking off Knuckles path in Marble Garden 2, IceCap 1 and Launch Base 2.
• By looking up or down and get hit or having Tails carry you. The screen is locked in position after being interrupted in relation to the character until he stands on flat ground. This allows for clipping through objects above, below and on walls.
• By Flash jumping as Hyper Sonic. Flash jumping defaults Sonic's speed to 8 pixels per frame while also briefly locking the camera and thus it's possible to go trough objects and sometimes solids.

Not fixed in any version.

Knuckles can hover in Hydrocity and Sandopolis

Just climb below one of those up and down moving pillars and get pushed down

It can happen in Sandopolis, too!

If you climb below one of the up and down moving rotating pillars in Hydrocity Zone, it will push you down without resetting you to normal status when you leave the wall, resulting in you climbing on nothing. The same thing can happen in Sandopolis Zone. This video might explain it a little bit better.

Not fixed in any version.

Glitches specific to Super/Hyper forms

Hyper Sonic's extraordinary abilities help to bring even more bugs and glitches into Sonic 3 & Knuckles. In particular, his double jump, which allows him to boost towards any of the eight main directions, can bring quite a lot of confusion to the mix.

Breaking the scrolling for the Mushroom Hill Zone boss

By double jumping before the screen gets locked vertically, Hyper Sonic messes up the level's scrolling. The level is still completable, though.

Not fixed in any version.

Double jump object collision

Hyper Sonic's double jump move is meant to destroy all the Badniks on screen, however it also interacts with other objects, such as the balloons and bumpers in Carnival Night Zone. Colliding with bumpers in this way causes the move not to work properly.

Should a Star Post be activated, Hyper Sonic will also "collide" with the stars on-screen when performing this move, causing the Bonus Stage to load.

Not fixed in any version.

Corrupt Lightning Shield graphics

If Hyper Sonic collects a Lightning Shield, and either runs out of rings or finishes Act 1, Sonic will revert to a his regular, shielded form as expected. However, the sparks created from the double jump move will be corrupted.

Not fixed in any version.

Eggman shares Super Tails' palette

Eggman's yellow cape and the seat of many of his vehicles share the same palette as Tails. This means when Tails becomes Super Tails, these elements will also glow.

Not fixed in any version.

Level-specific bugs

Angel Island Zone

Break the intro cutscene

Grab Sonic and chase Knuckles...

...to mixed results.

Or fly upwards to break everything.

During the introduction cutscene with Knuckles, control is taken away from Sonic, but not Tails. If Tails starts carrying Sonic and moves to the right, it's easy to temporarily or permanently break the graphics for the stage. Fly low and you can see Knuckles run through solid objects; fly high and the tile set can be corrupted.

This is a regression from the original Sonic the Hedgehog 3. There, it is much harder (if not impossible) to get Tails to reach the same distances before the title card loads in, meaning these issues are not seen.

Not fixed in any version.

Clipping into the ground

In the first loop on the low path, right before the waterfall, if you do a frame perfect jump and roll, you can clip into the ground. Zip to the left to fall out of bounds and die or right and jump to get out.

Not fixed in any version.

Get to Sonic's Act 1 boss area as Knuckles

Precautions were made to stop Knuckles from getting to the Sonic/Tails Act 1 boss area, but the design isn't foolproof, particularly with Super or Hyper Knuckles. With a very precise jump and glide, it is possible to reach the top of the spikes on the left hand side, and so get to the wrong route.

Doing so is not the best of plans, however, as while the camera will lock for Fire Breath, the boss will still spawn in the Knuckles area (i.e. below the player). With no means of defeating it through normal means, Knuckles will have to die. Conveniently, some of the vertical bombs make it up there to assist in this.

Using this oversight in conjunction with a Sonic 3 bug (allowing you to revisit Act 1 after exiting a Bonus or Special Stage), allows Knuckles to access Sonic and Tails' path through Act 2, and ultimately the Act 2 boss... which won't load in.

Not fixed in any version.

Sonic in Knuckles' path

By jumping at a specific height with the right speed, all characters can clip into the wall right above the blocks. However, there's an area (not an object) that kills Sonic and Tails on contact Video. To avoid this, Sonic has to lock the camera above him and have Tails clip him through the spikes to the right, just before the boss. Once inside, wait for Tails to respawn and have him carry you over the solidity to your right. Position yourself about at the end of the slope and jump to fall down and survive the deadly area. The boss then spawns like usual and Act 2 loads normally, but the level boundaries will be set for Sonic instead for Knuckles and thus Sonic will be unable to continue on this path.

Not fixed in any version.

Other Oddities

• When the first Fire Breath escapes, his hurtbox disappears but his hitbox for the flames remains.
• Depending on your speed when you enter the tubes, you can be slowed down or even roll all the way back to the entrance by pure chance. Sometimes you can even jump out of them which might save time in a time attack. This is especially noticable at the last tube in the end of Act 2 since new sprites have been loaded for the cutscene with the bomber.
• The crumbling platforms can sometimes be passed through by a bounce with a Water Shield for a single frame. This unlike e.g. Hydrocity Zone where you can pass through at any time after they begin to crumble or Lava Reef Zone where you have wait a specific amount of time.

Hydrocity Zone

Ramp glitch

Sometimes when running up 90 degree ramps, you'll clip into it and fall through inside the wall. Video

Not fixed in any version.

Getting through the solidity of edges

By very precisely jumping into a corner and bouncing with a Water Shield, it is possible to go inside the walls of the level and take shortcuts etc. Tails can simply fly into them as he can't land when his Y-velocity is larger or equal to zero. If then your X-velocity is zero when your Y-velocity reaches zero or less, the game simply lets you fall through the bottom if you're not close enough to the top.

Not fixed in any version.

Moving wall glitch

At the beginning of Act 2 when the left wall begins to move, if you're right next to the wall at the right place (slightly before the checkpoint), jump at a certain height (about where the rings are) and do an Insta-Shield or start to fly while holding right, and the moving wall will clip you into the ground. Since the Act transition was vertical, certain special boundaries are in place in order to prevent you from going back into Act 1 and thus a horizontal underflow is impossible unless the stage was loaded from fresh (i.e. level select, Special Stage or death). Video

Not fixed in any version.

Incorrect Hyper Sonic flash

When double-jumping as Hyper Sonic, the entire screen is meant to flash white. This happens on every stage except the second Act of Hydrocity, where a few tiles in the far background remain black.

Not fixed in any version.

Access Knuckles Act 2 route with Hyper Sonic

Jump up here

Looking for Warp Zone

Found it! Maybe.

One of the walls in the second Act isn't protected from Hyper Sonic's double jump, meaning the player can leave the top of the screen, run to the right (after jumping over a few obstacles) and get to the boss fight area for Knuckles. Both paths lead to a dead end as the boss never spawns, and if the player hits the Star Post and runs out of rings, they'll be forced to reset the game to continue.

Not fixed in any version.

Marble Garden Zone

Act 2 Boss in Act 1

Since this is a stage that wraps vertically, you can despawn the object that kills in the mudpits and since they're not solid from above it's safe to jump down right before the Act 1 boss and zip past it to enter the loopback area. If you get here and try to beat the Act "again" you'll eventually end up to an area that spawns the Act 2 boss inside a wall. It's only possible to get to the next stage with Sonic alone or Knuckles though as the game will mess up with Tails otherwise. It's also necessary to go down the lower path and then crouch at the part where the rectangular platforms usually get lowered into, otherwise it'll be impossible to break the capsule after. Then you can't get hit or jump at the right side of the screen so you have to find a good spot on the left side to attack the boss on. Finally to prevent a softlock or a death, you have to jump out of the wall at a certain place on the left side. Video

Not fixed in any version.

Knuckles vs. Sonic's Boss

End of the road for Knuckles...

...or not.

Good job Tails was here.

The second Act of Marble Garden Zone has a Relief placed slighty too high for Knuckles to reach, forcing players to backtrack and find a new means of getting through the level. However, with a spinning top Knuckles can get the extra height - either by jumping straight off, or by climbing the wall on the top left.

Defeating this Relief opens up the route intended for Sonic and Tails, meaning Knuckles can access their boss. This means Tails is spawned out of nowhere to assist the fight against Eggrobo.

Not fixed in any version.

Sonic/Tails vs. Knuckles' Boss

Get Sonic or Tails to the top left corner of the whole stage, right where the Mantis is. If you don't have a friend to help you and you don't want to play as Tails, it's most easily done by taking a spinning top to the top lefternmost corner you usually can get to and simply jump over the top. Once there, Spin Dash by the edge and let go in such a way that you won't drop too much after the moving platform. This should get you enough speed to go over the top again in which case you can drop down right by the pillar and zip left to do a horizontal overflow. You're on the lower part of a hill in the loopback now so Spin Dash up and if necessary jump with the right timing to avoid death and you'll be at Knuckles boss. Video

Not fixed in any version.

Carnival Night Zone

Barrel clip

By getting a Water Shield in Act 2 and bouncing on a barrel in motion, it's very easy to clip into walls.

Not fixed in any version.

Break the cannon to IceCap Zone

In regular Sonic the Hedgehog 3, the final cannon which is used to access IceCap Zone behaves like any other cannon in the level - the only difference is that on the third semi-rotation, it will automatically fire to the top right. This means by pressing a button, either player can fire in any direction they choose (although they'll not go anywhere meaningful).

In Sonic 3 & Knuckles, control is taken away from player one as soon as he/she enters the cannon. This does not apply to second-player Tails, however, meaning Tails can fire Sonic out of the cannon at any point. While Tails can then re-enter the cannon and fire at will, Sonic's control will still disabled, effectively locking the game (although as with other transitions, data is saved in advance, so IceCap will be made available through the save select screen).

Not fixed in any version.

Act 2 Sonic route as Knuckles

With no boss and a good chunk of the stage being skipped over with boosters, there is a sense that the Knuckles route of Carnival Night Zone Act 2 wasn't entirely finished, let alone tested. Seconds into the Act, Knuckles can work his way into Sonic's route by jumping and gliding on the first diagonal red/white spinning pole. An upper route leads to Sonic's area, and Knuckles can happily navigate the stage with no issues (though there is no water and the lights won't be turned off).

At the end of the Act, Sonic would usually meet Knuckles, who would jump on a switch to send Sonic flying upwards. When playing as Knuckles, this doesn't happen - you will be able to access what would usually be the end of Knuckles' route, but the capsule won't spawn and the teleporter won't work. Instead, Knuckles has to pretend to be Sonic again, climbing up the shaft and to fight the Graviton Mobile, piloted by Eggrobo.

Knuckles can leave the stage using the cannon in the same manner as Sonic and Tails, but will appear in IceCap Zone via a teleporter as intended.

Not fixed in any version.

Loopback area from the right side

Knuckles looking at the wall right after climbing up to Sonic's way to the boss.

Knuckles at the top of the aforementioned wall.

Knuckles gliding to the right

Knuckles reached the junk, and there is even more below

Taking Sonic's path as Knuckles in Carnival Night Act 2 as described above can allow Knuckles to scale a wall in the boss area. Climb up and glide to the right to reveal the loopback area - a part of the zone not meant to be seen.

Not fixed in any version.

IceCap Zone

Tails and ice cages

This bug from Sonic 3 has been made worse in Sonic the Hedgehog 3 & Knuckles. If Tails breaks an ice cage while Sonic is standing on top of one, Sonic's vertical position will "lock", allowing him to move left or right without being affected by gravity. Jump and gravity will take effect, though collisions continue to be wonky until Sonic interacts with an object.

When combined with slopes, this glitch can cause Sonic to get stuck in walls and access areas of the map he shouldn't be able to get to. In Sonic 3, something similar will happen, but it will affect Tails, not Sonic.

Not fixed in any version.

Launch Base Zone

Corkey Badniks do not affect climbing Knuckles

The laser attack from a Corkey Badnik does not affect Knuckles if he is climbing.

Not fixed in any version.

Sonic can fight Knuckles's boss in Act 1

If Sonic passes through the set of spikes near the start and under a collapsing platform and a huge rotating cylinder, he will zip to the right and arrive at Knuckles' boss arena. Two Twin Hammers will appear, but Sonic only needs to defeat 1 to proceed to the next level. However, Tails must lift Sonic to the ledge on top of the arena to avoid death when the next level loads. Sonic mustn't defeat both bosses at the same time, or the game will crash. The undefeated Twin Hammer can be destroyed without worrying about the game crashing; otherwise, it will follow Sonic wherever he goes. It can get quite annoying.

Not fixed in any version.

Post-boss foreground tiles

Orange!

Blue!

Red!

After beating the two Twin Hammers as Knuckles, the player will fall down to a lower area awaiting the signpost and the cue for Act 2. During this sequence, an animated section of ground (sharing tiles with the big horizontal spinning drums seen elsewhere in the level) goes through a couple of obvious and unwanted palette changes. It's first seen with the boss palette (grey/orange) and turns blue when the signpost drops down from the ceiling, before returning to its correct colours once the Act clear text comes through.

Launch Base is incorrectly pointing to post-Act 1 boss cleanup code intended for Mushroom Hill Zone, so the blue palette is from a completely different level.

Not fixed in any version.

Turn water white

If, at the start of Act 2, Sonic or Tails has a Lightning Shield, Spin Dashing into this Flame Shield will cause Sonic to spin into the water and quickly lose both. The underwater palette is meant to flash white when the Lightning Shield comes into contact with water, but in this situation it turns white... and doesn't turn back. The underwater palette will remain white until Sonic has died or has entered/exited a Bonus or Special Stage.

While technically possible in vanilla Sonic 3, it can't be seen in normal gameplay as no Flame Shield monitors are placed this close to water. In that game, this monitor is a Super Ring, while in Sonic 3 & Knuckles it is a Flame Shield. The reason for the change, like so many of Sonic 3 & Knuckles' alterations, is not known.

Not fixed in any version.

Access Knuckles area in Act 2

Get a bird to hit the switch...

...and get to Knuckles' area.

Towards the end of Act 2, Hyper Sonic and Super Tails can grant themselves access to a portion of Knuckles' area. A switch exists to allow Knuckles to rejoin the main path - it is visible in Sonic and Tails' playthrough, but being positioned beneath the player, it is normally impossible to hit. Hyper Sonic's ability to destroy anything on screen and the auto-targeting Super Tails' Flickys rectifies this, allowing both characters to reach this lower path.

There is little point in doing so, however, as not only is this going backwards down Knuckles' route, Sonic and Tails will eventually be met with a dead end. The area is also completely filled with water, meaning Super Tails is likely to drown.

Not fixed in any version.

Fight Sonic/Tails' Act 2 bosses as Knuckles

Spin dash here

Climb here

Lose here

Just before Knuckles enters his boss area, it is possible to Spin Dash up a ramp and "climb" up to the tubes above, thus getting into Sonic and Tails' route. Follow the path to the left and you'll get to Ball Shooter, piloted by Eggman.

The only issue is that normally Knuckles can't jump high enough to hit Eggman. Two options exist - with pixel perfect jumping and Hyper Knuckles, it's possible to defeat him, alternatively, being knocked back onto the ledge by one of the black balls can get Knuckles into a good position. After beating Eggman, a Knuckles-less cutscene will play and you'll get to fight wonky versions of Beam Rocket and Big Arm. Save for the change of scenery and camera problems at the end, this plays out much the same as the regular Knuckles game.

Not fixed in any version.

Lava Reef Zone

Hyper switch

One of the Giant Rings in Act 2 is accompanied by a floor switch, allowing Sonic and Tails to leave the room on the right hand side. However, the switch shares the same palette as the Giant Ring, so in Sonic 3 & Knuckles, it will flash "hyper" colours when the ring is visible. This isn't an issue in Sonic & Knuckles as the Giant Rings are always gold, and while theoretically all switches in this Act are affected, this is the only time both a Giant Ring and a switch can be seen on screen together.

Not fixed in any version.

Tails uses the wrong animation while falling with Knuckles's boulder

Good

That's no good

When Knuckles throws the boulder at the end of the second Act of Lava Reef Zone, Tails will use the wrong animation – facing sideways and rotating, rather than his 'hurt' sprite – if he's not playing alongside Sonic.

Fixed in Sonic Origins.

Sky Sanctuary Zone

Fight Knuckles' boss with Sonic and/or Tails

Unlike in regular Sonic & Knuckles, the level select allows Sonic and/or Tails to fight Knuckles' bosses in Sky Sanctuary Zone. Eggman appears instead of Eggrobo (and is destroyed during the fight), Tails is drawn behind the floating island if acting as Sonic's partner, and defeating Super Mecha Sonic leads to Knuckles' regular ending cutscene, albeit as "Blue Knuckles". Play as Tails and Blue Knuckles will have grown a pair of tails during this sequence.

Not fixed in any version.

Play Sonic's stage as Knuckles

Likewise, Sonic 3 & Knuckles has no objections to playing Sonic's Sky Sanctuary Zone as Knuckles through the level select, meaning yellow-sock Knuckles and green-sock Knuckles can finally meet. Beating the stage leads to Death Egg Zone which can also be accessed on the level select and finished without issue.

One might assume the sock colour is the only thing that separates the cutscene and playable Knuckles sprites, but in fact the cutscene version uses slightly pinker shades of red.

Not fixed in any version.

The Doomsday Zone

Play with Tails or Knuckles

Using the level select code, it is possible to play The Doomsday Zone as Tails or Knuckles. Both characters will appear corrupted (unless the user enters and exits edit mode before transforming at the start), but the level is fully playable. Knuckles starts the level in a slightly different location for some reason, while Tails doesn't automatically lose rings.

Finishing the zone as Tails leads to his regular, non-super ending. Finishing the zone as Knuckles triggers Sonic's normal ending, except with Knuckles sprites and odd palettes.

On its own, Sonic & Knuckles stops the player from playing the level as Knuckles, meaning this can only be seen (without hacking) in the locked-on game.

Not fixed in any version.

Unsorted

Hidden Palace

• Using debug mode during the scene where Dr. Eggman takes the Master Emerald will unlock the controls, enabling Sonic and Tails to move freely, and any uncleared Super Emerald there will warp the player to a Special Stage if Sonic lands on one. After finishing the Special Stage, the player will strangely appear on the spot of the last Giant Ring of Lava Reef Zone's Act 2.
• Using debug mode it is also possible to hit Eggman 256 times and he will explode.