This article contains a list of glitches from Sonic the Hedgehog 3 & Knuckles. Unless otherwise noted, all glitch names are conjectural. Many of them have not been confirmed by Sega.
List of glitches
- Angel Island Zone Music Glitch
This bug/glitch can be found shortly after the first encounter with Flame Craft. If the player enters and exits a Special Stage, the Zone's music would automatically change to Angel Island Zone Act 2's theme, although the title card states that it is still Act 1. This is also possible if the player enters a Bonus Stage.
- Vertical scroll:
To perform this glitch, the player must press and hold down until the screen moves, then jump. This can be used to skip over bosses, return to the beginning of levels, and to go past the Knuckles-only walls in IceCap Zone Act 1 as Sonic (This is caused because the stage is so tall that it vertically loops infinitely, and instead of the stage's 0,0 in pixels being in its normal position (at the very top left of the stage), it is instead locked onto the camera. So when the player goes above the camera, it causes in a integer overflow, resulting in a very large positive number (65,535), so the camera rapidly moves to the players current position, and while in this state, all sprites are unloaded, allowing the player to move into them).
- Upside down sprite:
To perform this glitch, the player must be in Flying Battery Zone Act 1 as either Hyper Sonic or Super Tails, and travel to a point after the first magnetic section with 2 moving cannon type robots. Just before a checkpoint, there is a switch which the player must fly/jump over to land on a raised ledge. Once there, they must continue forward until they get to a section where there are circles dug out of the ground with spike balls spinning around in them.The player should then push against the spike ball in the direction opposite of the one it's traveling in, and the character's sprite will then turn upside down.
- Activate Tails's flying ability with Sonic & Tails:
If the player holds the up button on the D-pad with Tails standing next to them, jumps, and uses the Insta-Shield, Tails will sometimes use his flying ability. The chance of this happening slightly increases if the player has an elemental shield. With the Fire Shield active, Tails will fly very far up until his AI forces him to return.
- Out of the Barrier:
In a very rare and difficult case, it is possible to glitch out of the barrier for the Barrier Eggman in Flying Battery Zone. This glitch can only be performed with Hyper Sonic. After the player hits the "eye", they have to perform the Hyper Flash/Sonic Boom. The timing needed for this is extremely precise, but if performed correctly, Sonic will glitch out of the left side.
It is also possible to glitch out the right side and move to the Hang Mobile, but this is more difficult to do. While on the path leading to the Hang Mobile, parts of the background sprites may be corrupted or the background may be all black. If this happens, it is likely that the normal background will rise up along with the platform.
- Endless Spin Dash:
This glitch can only be done in Sandopolis Zone and Carnival Night Zone. When the player is performing a Spin Dash charge on a break-away platform, they may fall into the sand. When the player manages to get on land, the character will automatically spin dash and will continue doing so for some time. In Carnival Night Zone, the player has to perform a spin dash on the ledge next to a spinning barrel. If the barrel comes to the player while charging the spindash, the dust will stay behind the character and the same thing from Sandopolis will occur.
- Speedy death in Carnival Night Zone:
There is a corner in Carnival Night Zone Act 1 where, if Sonic is going too fast, he will clip into the floor and die.
- Knuckles fights the Carnival Night Boss:
If the player takes the default path as Knuckles in Carnival Night Zone, the Egg Capsule will not appear and the end of Knuckles' level and the player will not be able to go through the teleporter and advance to IceCap Zone. If this happens, the player will be forced to climb up the tunnel that Sonic and Tails take and must fight Doctor Robotnik's Energy Ship, piloted by the Eggrobo. After the boss, the player can jump into the cannon and be blasted into IceCap Zone (Knuckles will still be shown entering the stage through the teleporter).
- Doomsday Zone with corrupted sprites:
This glitch can only be performed using the Level Select cheat code. It is possible to enter The Doomsday Zone as Super Tails or Super/Hyper Knuckles, although their sprites will be corrupted, and Super Tails will not lose Rings. The only way to avoid the sprite corruption outside of hacking is to enter and exit Debug Mode rapidly (by pressing B twice).
- Tails' invisible air spring:
In Flying Battery Zone, if the player jumps on an Egg Capsule with a Spring on top, Tails will follow. When the player is launched upward, Tails will also be launched, even though he didn't touch the spring.
- Knuckles vs Robotnik:
When playing as Knuckles, the player can fight any of the bosses and then die. When they fight the boss again, the pilot will be Robotnik instead of the EggRobo. For some reason in Flying Battery Zone, the boss will always be Robotnik.
Fixed in Sonic & Knuckles Collection
- Blue Knuckles:
After entering the glitched Angel Island, the player should activate Debug Mode, and follow the water all the way downwards until the game resets itself. Sometimes, the game goes to a blank white screen and later resets as well. After the automated reset, they must go back to the Level Select, and if the numbers 80, 81, or 82 are seen, the glitch is successful. They can then go to any Act and Blue Knuckles will appear. He cannot go through certain sections of a stage without the aid of Debug Mode, and when he reaches the Knuckles cutscene trigger in Hidden Palace the game will crash. Blue Knuckles has an immediate transformation between Super and Hyper, but he will be yellow with glitched afterimages and lack the ability to breathe underwater. When he reverts to normal, he will become Knuckles with Red Sonic appearing on the signpost. He is referred to as Tails (with a glitched sprite to the side) in the completion blurbs after clearing an Act or getting a Chaos Emerald/Super Emerald.
- Score/Ring Sonic:
This glitch can only be performed in Angel Island Zone with Debug Mode enabled. When the player is in Debug Mode, they can bypass boundaries. The player can abuse it to bypass the Act 1 boss and move on to act 2 without any boss fight. They must use it to enter the inside of a loop and cause their death. When they respawn, they will have a corrupted ring sprite instead of Sonic. If the player beats the Act 1 boss using that corrupted character without any additional use of Debug Mode, Sonic's sprite will not return to normal. This means that the player can go on through Act 2 with Sonic in this state. However, falling into the next zone changes him back to normal.
The glitched character has a hyper form, although there are no changes upon entering it outside of a blue spiky Sonic palette.
The reason this only works in Angel Island Zone is because there is no way to bypass the boundaries, since the Act 2 maps will be loaded on the character's standing position. Additionally, when the flame attack switches the sprites and colors of the Zone, Act 2 begins to load. This also explains the Sonic the Hedgehog 3 only glitch that changes the music to Act 2 when entering a bonus stage and exiting.
- Level warp:
There are two methods of performing this glitch. The first is to defeat Knuckles while using Tails to help Sonic stay above the ground. After defeating Knuckles this way, the player will have full control over Sonic in the cutscene where Knuckles tries to stop Robotnik from taking the Master Emerald. The other method is to use Debug Mode to bypass everything and reach this point. If the player jumps into one of the deactivated Super Emeralds they will enter a Special Stage (there is a possibility that the 8th Sonic & Knuckles Special Stage will be loaded). If they touch a Red Sphere to exit, the results screen will show up as usual (or if the second method was chosen, the background will have four rings on each side of the screen), although after the score is done racking up, the game will warp the player to the last Giant Ring they touched.
- Angel Island warp crash:
To perform this glitch, the player must first use the Level Warp Glitch. If no Giant Rings were touched they will end up back in Angel Island Zone, but the screen will be positioned far above the normal starting part of Act 1. The camera will then glitch downward while the game plays a buzzing sound. After some time, the color of the grass will turn red and the sound for the airship from Act 2 will play. The game will then crash.
- Bonus/Doilus Stage Crash:
There is a small chance that performing the Level Warp without touching any Giant Rings will cause a strange sound to play, making a corrupted Bonus Stage title card saying "Doilus Stage" appear on-screen and crash the game. There is a possibility that the text displayed will be different, such as "Cohtil Ilrage" or "ROU*V V*ORSE."
- Ring number glitch:
If the player somehow obtains more than 999 Rings by breaking S Monitors, instead of going to 1,000, the game will pick a different HUD sprite in place its place ("i.e" E49 Rings).
- Crashing into Sonic and Knuckles (S Monitor Overload):
To perform this glitch, the player can go to any level (excluding Doomsday Zone) with Debug Mode enabled. They should then place a large number of S Monitors down and roll into them to enter their super form while gaining a large number of rings. They must repeat the process until the controls become locked. After the controls are locked, they should push start, and the game will take the player into Sonic and Knuckles. However, if the player presses A + UP on the title screen, they will be taken to the Sonic 3 & Knuckles Level Select menu instead of the Sonic & Knuckles-only version. When activating the glitch, there is a chance that the game will make corrupted sprites appear, and will usually reset itself if this happens.
- Music Box Crash:
In prototype 408 of Sonic 3C, if the player goes into Debug Mode and places a checkpoint in the air during the opening sequence (Tails flying toward Angel island with Sonic Jumping off the plane, turning into Super Sonic) and then dies, the level will start the sequence over. This time, when Sonic reaches the island (where Knuckles comes out of the ground and knocks the Emeralds out of Super Sonic), the game goes to a blank white screen and crashes. Next, the game begins to play Angel Island's music in a music box-like manner. This has been fixed in later versions. Video of this glitch
- Angel Island credits glitch:
In prototype 517, if the player were to place a checkpoint during the opening sequence of Angel Island, in Debug Mode and then let Sonic fall to his death, the game will warp him to the credits, where both the credits screen and music will fade in an out. Video of this
After the ending of every Act is a loopback. In these loopbacks, the Acts have most of their objects removed, and the ones that are not removed do nothing; for example, spikes that are not removed do not hurt the player, nor does lava in Lava Reef Zone. Additionally, loops do not work, as well as some other glitches. Some loopbacks are normally accessible, some can only be accessed with Debug Mode, and some cannot be accessed at all. After each loopback is another loopback, which continues until the character's coordinates max out. The game will then restart the stage at the proper location.
- Accessible Loopbacks:
- Loopbacks only accessible with Debug Mode:
- Inaccessible loopbacks:
All other loopbacks are inaccessible, normally because the screen locks too early. One exception is IceCap Zone Act 1, where it is inaccessible because when the player moves far enough to the right before the miniboss, Act 2 loads almost immediately (This can be averted by performing the checkpoint glitch). Additionally, Lava Reef Act 1's loopback may appear to be inaccessible, but there is a glitch that allows the player to move further to the right after Act 1 is completed (doing this will cause Act 2 to not load).
- Hydrocity Zone Act 2 Clip:
This glitch takes place in Hydrocity Zone, after entering Act 2. When the player gets to the section before the 1-Up monitor (the area where they must Spin Dash through some breakable walls), by jumping and rolling sporadically against some of the walls (specifically by using the invincibility frames one gets during the Insta-Shield), they can theoretically bypass them by having the moving wall push Sonic through them. The result of this is, however, is that the player will get stuck above the wall, and the only way out will be to either leave the game or wait for a Time Over.
• Mushroom Hill Zone Switch Glitch
This glitch takes place in Mushroom Hill Zone. If, during Sonic's or Tails' playthrough, the player was to stand on the Switch to open the door immediately after the Knuckles cutscene in a certain way, they can make the Switch cycle between pressed and non-pressed every frame, which makes the Switch's animation and sound effect spaz out.
- Angel Island Airlift Sprite Glitch
During the cutscene where Knuckles steals the Chaos Emeralds, its possible for Tails to air-lift the player during the cutscene. When moving past knuckles, it can cause some sprite errors.
Vice versa It Is possible for Sonic to enter Knuckles' second Act in Angel Island Zone. To perform this glitch, first enter a bonus stage or a Giant Ring as this will unload the invisible barrier that is preventing the player from backtracking. Go to the area just before the Act 1 boss, then go onto the last spike and look up until the camera pans up. Have Tails fly the player until the spikes are off screen and then lower down until they pass through the spikes.
Once the player lands inside the wall, they should be careful not to move much in the horizontal axis as the barrier that kills Sonic when they try to bypass this wall is right next to them. Wait for Tails to rejoin and have him fly the player just slightly below the grass on top of the barrier. It will only kill the player if they touch its side. Walk to the left and the player should end up past the barrier and in Knuckles' Act 2. However, due to the camera normally not being this low, the stage will cut off early and lead to a bottomless pit.
The same can be done with Knuckles. While assuming Super Knuckles or Hyper Knuckles, jump up to the highest spot and glide to the top of the next set of spikes, which the player should climb up. If the boss has not been defeated here, it then will spawn Knuckles into boss arena and the player will not be able to attack. If the boss has already been defeated, then there will be no water in Sonic's Zone. When they player reaches the auto-scroll section, it will not auto-scroll. The path back will be blocked off, and there will be a barrier preventing the player from progressing.