Proto:Sonic & Knuckles/Sonic 3C 0408

This is a sub-page of Proto:Sonic & Knuckles.

Download Sonic 3C (0408 Prototype) File: Sonic 3C (0408 Prototype).bin (4 MB) (info)

To do: Theres still several more things to document, Pre-0408 versions of objects, etc. This should be a good place to start.

The April 8, 1994 prototype of Sonic 3C was released by drx during the February 23, 2008 proto release. It is a prototype of Sonic 3 & Knuckles, and, by extension, Sonic & Knuckles. Much of the Sonic & Knuckles portion and the Knuckles-exclusive paths in Sonic 3 are in the process of being implemented in this build.

This build, alongside the subsequent prototype, is often mistook for a prototype of a canceled Sonic 3/Sonic & Knuckles compilation called Sonic the Hedgehog 3: Limited Edition, whose existence was reported in gaming magazines at the time. In actuality, "3C" was the codename for the entire Sonic 3 project, with Sonic the Hedgehog 3 (Sonic 3A) and Sonic & Knuckles (Sonic 3B) being split from it.

Cheat Codes

Level Select is enabled by default, so you can just go down to Sound Test at the title screen.

In the Sound Test, you can enter the following combinations:

• 01, 03, 05, 07 - Enables debug mode.
• 02, 04, 06, 08 - Get all the Chaos Emeralds.

You can also use patch codes FFFFE2:0001 and FFFFFA:0001 to enable debug mode.

General Differences

Note: S3 = Sonic the Hedgehog 3, S&K = Sonic & Knuckles

• Knuckles is selectable in 1-Player mode.
• Some of Super Sonic's sprites are garbled when interacting with certain objects in the S&K zones.
• Tails and Knuckles have incomplete Super forms, since the art has yet to be implemented, thus Knuckles cannot turn Super by normal means. Likewise, Hyper Sonic is not in the game yet.
• Due to Hyper Sonic not being in the game yet, "S" monitors will only transform you into Super Sonic, and will still play the incorrect sound effect like in Sonic 3.
• The ending sequences have yet to be implemented.
• No glowing Special Stage rings are present in the S&K zones.
• The save format is identical to the one found in Sonic 3. You can play a saved game past Launch Base Zone, but when you exit the game, the save will be indicated as "Clear", and only Zones 1 through 6 can be selected. There are also only 6 save files as opposed to 8 in Sonic 3 & Knuckles, and lives and continues are not saved or shown. (The final Sonic 3 actually had 14 save images; 6 for S3 only, 8 for Sonic 3&K.)
• Knuckles has a different underwater palette.
• The music for the title screen, mini-bosses, Knuckles, invincibility, and collecting 1-ups are all from Sonic 3.
• The Data Select music bug from Sonic 3 alone is still there.
• The Super Sonic water shield bounce glitch from Sonic 3 is still present.
• Pressing A while the game is paused returns you to the level select screen rather than the SEGA logo screen.
• Many sound effects are missing, especially in the Sonic & Knuckles Zones and when playing as Knuckles.
• Monitors placed with debug are Lightning Shield monitors, rather than Super Sonic monitors.
• Blue Knuckles still appears on the goal signpost when playing as Sonic or Tails. Likewise, a red Sonic is shown on the signpost when playing as Knuckles.
• Monitor behavior is the same as in Sonic 1-3 in this build, where you have to jump on a monitor to break it, and hitting it from underneath makes it fall.
• The following levels cannot be accessed in the level select. Enabling debug mode removes these restrictions, allowing you to enter them:
  • Lava Reef 3 & 4 (Act 2 Boss & Hidden Palace)
  • Sky Sanctuary 2
  • The Doomsday 1 & 2 (Doomsday & Death Egg Final Boss)
  • Bonus 1 & 2 (S&K Bonus Stages)
  • Special Stage 1 & 2
• On a Japanese system, the trademark symbols are not removed from the SEGA logo and title screen, and Tails' life counter does not become "Miles" even though the results tally changes to "Miles".

• In this build, Tails's rotational running sprites are different - his tails are separated from the rest of his sprites unlike the final. Mistakenly, they never show up in-game.

Zone Differences

Angel Island Zone

Sonic 3/3C 408	Sonic 3 & Knuckles

• Act 1 will still play Act 2 music when returning from a Bonus Stage after the Zone has been set on fire, like in Sonic 3.
• Knuckles can't shatter the rock that allows access to Sonic's path, and because of this he can take that route. However, the boss always spawns in Knuckles' path, causing him to become stuck.
• Knuckles' route in Act 2 still has its object layouts from Sonic 3.

Hydrocity Zone

• Knuckles' route in Act 2 has no rings, enemies, or checkpoints.
• When fighting the Big Shaker, the game plays the Sonic 3 mini-boss theme instead of the Act 2 boss theme (Sonic 3 final plays the Act 2 boss theme, but switches to the Sonic & Knuckles mini-boss music if the drowning timer starts and you get out of the water; Sonic 3 & Knuckles final plays the Sonic & Knuckles Act 1 mini-boss theme.)
• The spring that sends you backwards at the beginning of Act 2 is replaced with a 1-Up, which is the same as Sonic 3 & Knuckles final but not Sonic 3 final.
• The Screw Mobile's twister can still glitch out Super Sonic like it did in Sonic 3.

Marble Garden Zone

• The Act 1 miniboss crash glitch from Sonic 3 that can be achieved with a second player is still present.
• The start of Sonic's segment in Act 2 does not have a wall to prevent Knuckles from defeating the Relief, and instead has an extra set of spikes. Knuckles can hurt himself, stand on the spikes during the brief moment of invulnerability, then jump into the Relief's eye and destroy it, allowing access to Sonic's segment.
• Knuckles can climb on walls during the moving walls sections in both his route and Sonic's.

Carnival Night Zone

• When playing as Sonic alone in Act 1, Tails randomly appears after the boss. (This randomly happens in the completed Sonic 3, but with a different frequency.)
• Knuckles does not run in at the start of Act 1,
• Knuckles' route in Act 1 still has its object layouts from Sonic 3.
• Knuckles can climb the walls during the Bowling Spin boss fight. In the final version, he can't.
• In the room where Knuckles would go through the breakable wall to his own path in Act 2, there is still a spinning barrel. This was removed in later prototypes and the final and replaced with spikes to stop Knuckles from taking Sonic's path instead.
• Knuckles' route in Act 2 does not end with a Prison Egg, but the teleporter that goes to IceCap Zone is functional, anyway.
• When playing the game normally as Knuckles, after you defeat the Act 1 boss, the game freezes a few seconds after the signpost lands and after Knuckles' victory animations.

IceCap Zone

• In Act 1, when Tails first descends while playing as Sonic and Tails, the graphics are screwed up: the snowboard intro overwrites Tails' tiles with the snowboard's, and when the snowboard disappears, Tails' tiles should load. However, Tails' AI doesn't allow this to happen fast enough, and thus proceeds to draw Tails with some of the snowboard's tiles still remaining. Only when Tails lands does the tile swap complete, and Tails returns to normal.
• The floating icicle spheres in one of Knuckles' routes can hurt Super Sonic, just like they did in Sonic 3.

Launch Base Zone

• The background in Act 1 is a little glitchy.
• The object layouts for both Acts have been changed to the ones seen in Sonic 3 & Knuckles.
• The elevator poles at the end of Act 1 are not removed when playing as Knuckles.
• As soon as Knuckles defeats one of the Twin Hammers, the normal Act 1 theme resumes while the other Twin Hammer is still alive.
• A suspension pole near two submerged teacup elevators near the end of Act 2 isn't solid. It was made solid in later prototypes and the final to prevent Knuckles from riding the elevators and taking Sonic's path.
• Knuckles does not fight the Big Arm at the end of Act 2, and the boss music does not stop playing when the Prison Egg appears.
• The bubble graphics in Act 2 appear glitched.
• Sonic no longer fights the Big Arm after the Laser Columns boss.

Mushroom Hill Zone

To do: Map comparisons would be a good idea to have here.

• The level layout of both Acts is different, and the differences are very noticeable at the start of Act 1. Knuckles starts at the top of the level with Sonic and Tails starting lower down instead.
• Sonic and Tails just drop down in their standing poses instead of Tails lifting Sonic into the Zone.
• Knuckles does not run into any giant rings at the start of his Act 1.
• The giant ring in Sonic's area in Act 1 does not flash.
• If you enter the aforementioned giant ring without all the Emeralds, you'll be sent to the Hidden Palace chamber with Death Egg Act 2 music playing, then instantly warp to a different Special Stage.
• One bonus room in Act 1 contains a diamond cluster of rings. It was changed to a giant ring later in development.
• Hei Ho's axe can hurt you.

• The lever that Knuckles pulls down repeatedly in Act 2 has a blue handle. In Knuckles' game, the lever doesn't appear at all.
• A giant ring at the start of Sonic's Act 2 (after the Knuckles cutscene) is missing and has a bit of Russian Roulette action in its place. There are two monitors wedged in the ceiling, one of them is a 1UP monitor while the other is a Robotnik monitor.
• There is no giant ring near the pulley that takes you to the boss in Act 2.
• The Act 2 boss starting position is shifted to the left slightly from the final. This allows you to score endless hits on the boss without destroying the satellite, and the battle won't start until you hit the satellite itself, thus it was changed in the final so the player cannot do this. These hits also don't count toward defeating the boss.
• The Act 2 boss does not explode when killed until he crashes into the tree, and you must hit him six times after he has zoomed off.
• During the transition to Flying Battery with Sonic and Tails, Tails won't stop running to the right and will kill himself in the pit.

Flying Battery Zone

• The echo track of Act 1's music will go off-sync after looping, and will slowly drag more and more behind the lead melody as it continues to play.
• Various objects are missing in some places, such as badniks, hooks and rings.
• There are no giant rings in either Act.
• Some of the magnetic platforms are embedded in spikes. They can still hurt you if the platform isn't raised.
• Gapsule's position is about 16 pixels to the left in comparison to later prototypes and the final. The coordinates are the same as in Sonic 3.

• A double set of doors in Act 2 don't open completely.
• A few level design differences. For example, the pendulums in Act 2 are missing, and in the area after the Act 2 miniboss there are two ring monitors in place of a red spring, and there are no spikes.
• Some of the elevator shafts do not have spikes, and some that go upwards do not crush the player at the ceiling, instead pushing them through it.
• There is an erroneous chunk placement in the background near the end of Act 2.
• Robotnik stops exploding as soon as he begins to fly away.
• Your character does not automatically roll when he busts down the door during the transition to Sandopolis Zone. They appear to be rolling in the Sandopolis intro, though.

Sandopolis Zone

To do: Maps are present, but for some reason, they don't show up on the site at all. Find a way to fix this.

• Your character enters Act 1 in a rolling state, but does not get stuck in the sand. The controls aren't even locked at all, meaning you are permitted to move left or right before you land.
• Some more object layout differences.

Sandopolis Zone Act 1

Sonic 3C 0408
Error creating thumbnail: convert: ../../magick/quantum.c:216: DestroyQuantumInfo: Assertion `quantum_info != (QuantumInfo *) NULL' failed. /usr/bin/timeout: the monitored command dumped core /var/www/tcrf/includes/shell/limit.sh: line 101: 27929 Aborted /usr/bin/timeout $MW_WALL_CLOCK_LIMIT /bin/bash -c "$1" 3>&- Error code: 134
Final (Sonic & Knuckles)
Error creating thumbnail: convert: ../../magick/quantum.c:216: DestroyQuantumInfo: Assertion `quantum_info != (QuantumInfo *) NULL' failed. /usr/bin/timeout: the monitored command dumped core /var/www/tcrf/includes/shell/limit.sh: line 101: 27934 Aborted /usr/bin/timeout $MW_WALL_CLOCK_LIMIT /bin/bash -c "$1" 3>&- Error code: 134

• The first of Knuckles' alternate routes in Act 2 does not lead to the sand slides, instead forcing you to drop back down into Sonic's route.
• The rising sand in Act 2 rises more slowly.
• In the rising sand sections, all three shields and a 1-UP are tucked away in a corner. They are later replaced with a Super Ring and a Super Sneakers monitor.
• The area where there would be a very long slide in the final is very different. It is a series of slides which also includes a loop-de-loop that uses level chunks which are completely absent in later prototypes and the final.

Sandopolis Zone Act 2

Sonic 3C 0408
Error creating thumbnail: convert: ../../magick/quantum.c:216: DestroyQuantumInfo: Assertion `quantum_info != (QuantumInfo *) NULL' failed. /usr/bin/timeout: the monitored command dumped core /var/www/tcrf/includes/shell/limit.sh: line 101: 27939 Aborted /usr/bin/timeout $MW_WALL_CLOCK_LIMIT /bin/bash -c "$1" 3>&- Error code: 134
Final (Sonic & Knuckles)
Error creating thumbnail: convert: ../../magick/quantum.c:216: DestroyQuantumInfo: Assertion `quantum_info != (QuantumInfo *) NULL' failed. /usr/bin/timeout: the monitored command dumped core /var/www/tcrf/includes/shell/limit.sh: line 101: 27944 Aborted /usr/bin/timeout $MW_WALL_CLOCK_LIMIT /bin/bash -c "$1" 3>&- Error code: 134

Lava Reef Zone

• Even more object layout differences.
• Knuckles doesn't run in at the start of Act 1. He just stands there.
• Knuckles can destroy the four pistons of the driller robot by gliding into them before it begins drilling.
• Shields do not protect you from the debris of the exploding rock badniks.
• The bonus monitors at the end of Act 1 are visible for some reason, and for some stranger reason, the monitors have reversed gravity when released by the goal sign. When Act 2 begins, any monitors that have gone off the top of the screen can be seen underneath the ground.

• The lava at the end of Act 1 does not cool when Act 2 begins, but you can still walk on it.
• Act 2's palette has yet to be changed to indicate a freeze-over.
• The screen does not lock behind your character after having passed the first flamethrower.
• When you encounter Knuckles, his theme does not play, and he laughs after punching the boulder at you. The boulder doesn't make any sounds and won't cancel your Super form.
• The Act 2 boss area does not play the boss theme at the start. It plays it as soon as the boss emerges from the lava.
• The Act 2 boss area does not have a Lightning Shield. The ring pattern is also different.
• The lava in the boss area does not cool after breaking the Prison Egg. Instead, once the results tally has finished, the platform you're standing on will drift to the right a bit, then you'll have to jump across more platforms as the lava can still hurt/kill you. The level music does not resume, either.
• The tunnel at the end of Sonic's Act 2 does not go to Hidden Palace, so you're basically stuck. Knuckles' exit to Hidden Palace works, though.
• Without debug mode, the boss area cannot be accessed directly from the level select.
• An unused screen shake used for Act 3. Can't be activated using normal means.

Hidden Palace Zone

• This Zone does not play Lava Reef Act 2's music, but Sky Sanctuary's.
• The title card refers to this zone as Sky Sanctuary Zone Act 1.
• The player does not run in at the beginning.
• The screen locks the way back to the starting area after you pass the first set of spikes. The lock is set to happen at X coordinate 0500 where a foreground palette change from purple to green would occur.
• A Fire Shield is present in place of a Ring monitor, near the teleporter that leads to Knuckles.
• In the hidden area, there's a Super Sonic monitor instead of a Super Ring monitor, and three 1-Up monitors instead of one. As debug mode places Lightning Shields instead of "S" monitors in this build, this is the only "S" monitor in the game.
• The hole in the background isn't properly lined up with the teleporter before the Knuckles fight.
• The above-mentioned palette change screws up if you enter a Bonus Stage and come back, causing areas to be purple when they shouldn't be (e.g. the teleporter and the Master Emerald's altar).
• The Knuckles battle plays the Sonic 3 miniboss music. After defeating Knuckles, the music doesn't stop, and continues to play through the Master Emerald theft scene.
• Knuckles can hurt you when you have any form of invincibility state, including invulnerability states after getting hit, an invincibility powerup, and Super Sonic. He can even hurt you if you're in debug mode placing an object, at which point Sonic's graphics might be corrupted.
• Beating Knuckles does not cancel your Super form.
• At the start of the Master Emerald theft scene, Knuckles just stands on the ground looking upward as Robotnik pulls up the Master Emerald. When Robotnik attempts to escape, Knuckles doesn't hit him, and just grabs on to the emerald.
• The controls are locked with Sonic looking upward when Robotnik shocks Knuckles, but if you use debug you can remove the control lock, though you can't hit Robotnik and you can stand on top of the Master Emerald.
• After regaining consciousness, Knuckles will charge through the breakable wall, rather than stopping in front of it and punching it.
• When you approach the teleporter that leads to Sky Sanctuary, there is no cutscene. The controls and camera won't lock, and Knuckles won't jump on the teleporter. You can stand on it to activate it, anyway.
• This Zone cannot be accessed in the level select without enabling debug mode.

Sky Sanctuary Zone

To do: Get a video of Sonic's Act 2 boss.

• Once again, more level layout differences.
• Both Sonic's and Knuckles' versions of this Zone are considered to be Act 2 as the above Zone counts as Act 1.
• The air ducts are not active while Knuckles is en-route to enable the bridge in Sonic's Act, allowing the player to die by mistake.
• There seems to be some palette conflicts.
• The bouncy clouds don't seem to animate.
• The screen lock works differently in the Green Hill Zone boss fight, and the teleporter emerges in different positions.
• After the Metropolis Zone boss has been defeated, the balloons don't pop until they reach the ground.
• After beating the Green Hill and Metropolis bosses, the timer freezes and Sonic loses the ability to turn super. Dying or entering a Bonus Stage fixes the problem.
• After defeating Mecha Sonic at the end of Sonic's Act, the game cuts straight to Death Egg Zone with no results tally or cutscene.

Prototype	Final

• This prototype features an earlier version of the Eggrobo badnik sprite featuring a slightly different torso and head design. It was updated by the time of Sonic 3C 0517.

Sky Sanctuary Zone Act 1

Sonic 3C 0408 including background layer
Final including background layer (Sonic & Knuckles)

• Knuckles' Act does not have any rings, and the teleporter is absent.
• Pausing and returning to the Level Select from Knuckles' Act messes up the Level Select background slightly.
• As soon as the final boss theme plays, the normal Act 2 boss theme starts up again.
• Doomsday Zone music does not play in the second half of Knuckles' final boss fight.
• The screen does not flash when Mecha Sonic becomes Super Mecha Sonic.
• Some of Super Mecha Sonic's poses are a bit different.
• When Super Mecha Sonic is defeated, he does not land on the ground and drops off the screen, and nothing else happens after that.
• The Floating Island overlaps the Master Emerald.
• Knuckles' Act 2 boss fight behaves normally as Knuckles, but if loaded as Sonic or Tails, the boss will be very broken. It seemed to have been used as a test.

Death Egg Zone

• The player does not run in at the beginning.
• The overscan border color for Act 1 is red, instead of black like the other zones.
• There are a few object layout differences, with notable ones being the absence of rings and monitors in some bonus rooms.
• Many sound effects are missing, and the missile launchers play a different sound when firing.
• Red Eye's pillar overlaps the player and has tile transparency issues.
• The explosions seen when Red Eye moves to phase two last longer than usual.
• Red Eye's laser overlaps the floor.

• The palette changes too soon when transitioning to Act 2. In Sonic & Knuckles 0525 and later, the palette is changed after the Act 2 transition completes.
• If the signpost has been hit before landing, it'll fall at an angle when the floor explodes during the Act 2 transition.
• Tails has an animation error during the Act 2 transition.
• Act 2 ends with a Prison Egg after the Act 2 miniboss is defeated, then the player moves on to The Doomsday Zone, regardless of whether or not they have all of the Chaos Emeralds.

Death Egg Zone Boss

• The final boss (accessible by selecting Doomsday Act 2 in the level select with debug mode active) is really incomplete, only having a background, a few rings, no title card, and various poses of the final boss laid out throughout the act. There's nowhere to stand on, so you'll fall and die over and over.
• There are also prototype floor graphics with a different design located in the final boss area:

Prototype	Final

• The graphics for the crushing fingers and flame thrower already exist in the ROM, but these go unused.

The Doomsday Zone

• Really incomplete, only having the boss graphics and a background with no Super forms available, so you'll just fall to your death repeatedly. You can use debug mode and fly over to a section with glitchy collision.
• The background palette used here is different from the final and is more consistent with the colors seen in Death Egg Zone Act 2.
• The HUD and ring palette is incorrect here.

• At this point, the level layout only contains a line of placeholder rings and a single ring contained in the object layout. The start location does differ slightly however. The prototype level places Sonic at X $0140 and Y $0020, whereas the final is X $0000 and Y $0100.
• Other graphics for the Zone such as asteroids and missiles already exist in the ROM but go unused since none of the coding is present here.

Bonus Stages

At this point in development, the Sonic & Knuckles bonus stages are very unfinished. In normal play, Starposts will randomly send you to either the Gumball Machine or the Slot Machine when you hit it with at least 50 rings. The color of the stars is always white.

Glowing Spheres

Sonic 3 Nov 3rd, 1993 Prototype	Sonic 3	Sonic 3C 0408

Sonic 3C 0517-S&K Final

• This Bonus Stage is vastly incomplete, and thus does not appear in normal play. The only way to access it is via level select with debug mode active.
• No collision, partially complete graphics, and a preliminary animating background. As a result, you can only really die there.
• Since the graphics are partially complete, there are some that don't even appear in the final.
• The palette for this Bonus Stage is exactly the same as the one in Sonic 3, and does not cycle.

Slot Machine

Sonic 3C 0408	Sonic & Knuckles 0608-Final

• The layout is vastly different, with more rings (a total of 64 compared to S&K final's 24) and no GOAL blocks when starting the level (the borders still turn into GOAL blocks, though).
• The background is completely static. The little objects don't rotate and nothing scrolls.
• There is a higher chance of getting 3 Robotnik pictures on the slots than in the final version.
• Using debug to fall out of the stage causes the game to crash. In the final, it takes you to a glitchy area with randomly placed tiles, a la Sonic 1.

Special Stages

The Special Stages for the Super Emeralds are completely different from Sonic & Knuckles. The colors are exactly the same as the Special Stages of Sonic 3, but the sphere arrangements are completely different. Some of these layouts would become different Special Stages, and some would be outright dropped altogether. For example, the planned third Special Stage in 3C became the hidden eighth in Sonic & Knuckles.

Special Stage 1

Sonic 3C 0408	Sonic & Knuckles

Special Stage 2

Sonic 3C 0408	Sonic & Knuckles

Special Stage 3

Sonic 3C 0408	Sonic & Knuckles

Special Stage 4

Sonic 3C 0408	Sonic & Knuckles

Special Stage 5

Sonic 3C 0408	Sonic & Knuckles

Special Stage 6

Sonic 3C 0408	Sonic & Knuckles

Special Stage 7

This version uses the exact same object layout as the seventh Special Stage as Sonic 3's. It might have been just a carryover given the nature of development both games share.

Sonic 3C 0408	Sonic & Knuckles

Special Stage 8

Sonic 3C 0408	Sonic & Knuckles

Unused Graphics

Sprite	Description
	The data select screen only allows picking one of the original Sonic 3 stages. After beating Launch Base Zone, it marks the slot as "CLEAR" with the character portrait. However, the level icons for the S&K Zones are already present in the prototype, they just don't get utilized. Flying Battery Zone still uses the old icon from Sonic 3, Lava Reef's lava fall doesn't come down from the ceiling, Death Egg's conveyor belt ride has the pillar more centered obstructing more of the background compared to the final version, and Hidden Palace's icon is missing entirely. The Lava Reef Zone and Death Egg Zone icons also look slightly different from the final in terms of scenery.
	An early Super Sonic ending sprite exists unused. Compared to the final, Sonic has thinner pupils and the sprite is mapped to the Sonic 3 ending palette. It also exists in a few later prototypes.
	Early dolphin sprites seen in the good ending of the final game. It seems at this point they were intended to use a different palette, although nothing has yet been found to match.
	Early sprites of the Tornado flying off into the distance which mistakenly lacks the rocket booster seen throughout the rest of the game. This oversight persisted into Sonic 3C 0517 and Sonic & Knuckles where it appeared in early drafts of Knuckles's ending cutscene.
	Early sprites of the swinging pendulum object from Flying Battery Zone Act 2. The object was not yet programmed, so these are never seen.
	Unused sprites of Sonic swinging. These did not exist in Sonic 3. They remain unused in the final.
	Unused sprites of Tails swinging. These were partially overwritten in later prototypes and the final game by Tails' super transformation sprites.
	Unused sprites of Knuckles swinging. Same as above.

Pre-0408 Objects

Deeper within the ROM, there are graphics for even earlier versions of some objects that come from a build predating S3C0408.

Sprite	Description
	Earlier Sky Sanctuary Zone Collapsing Platforms that are more consistent to the stage's overall look.
	Earlier Hoist Wheel for Sandopolis Zone with an almost entirely different design.
	Earlier Mushroom Poles for Mushroom Hill Zone that would have been wooden instead of metal.
	Earlier version of the Death Egg sprite seen in the background of Lava Reef Act 2. Unlike the final, it is mapped the enemy palette and does not palette cycle.

Unused Level Chunks

Several level chunks aren't used, but can still be seen in the game's data.

Flying Battery Zone Act 1 & 2

• 

  CA

• 

  D3

Lava Reef Zone Act 1

• 

  E2

Lava Reef Zone Act 2

• 

  1F

• 

  20

• 

  47

• 

  4A

• 

  4B

• 

  87

Hidden Palace Zone

• 

  18

• 

  43

• 

  5D

• 

  75

Sky Sanctuary Zone

• 

  4C

• 

  50

• 

  89

Death Egg Zone Act 1 & 2

• 

  63

• 

  64

• 

  66

• 

  67

• 

  B6

• 

  B7

• 

  E0

• 

  E5

Sonic 3 Ending Leftovers

The Big Arm final boss from Sonic the Hedgehog 3 is still completely intact and can be hacked back into the game. The boss behaves as normal and is able to be defeated. Once this happens, the ending from Sonic the Hedgehog 3 takes place and the credits begin. However, since Knuckles is here this time, he has his own broken ending. Knuckles uses all his correct poses until the giant Sonic sprite shows-up which causes Knuckles's palette to get messed up. For some reason, the screen fades to the credits a good bit faster than it does for Sonic & Tails. This could be a possible leftover from an incomplete ending for Knuckles in Sonic 3.