The intro features Sonic riding a surfboard into Angel Island Zone. In the final game, Sonic rides the Tornado, jumps off, and turns into Super Sonic. The surfboard Sonic object still exists in the final game, but goes unused.
The only way to see this intro is if you wait on the title screen for the demo. Getting into Angel Island Zone Act 1 normally does not play the intro.
Knuckles also has completely different sprites, and simply blocks Sonic's path instead of punching him out and stealing the Chaos Emeralds. Because they share the same palette, Knuckles also causes the HUD text to turn green; the developers actually implemented two different fixes for this in the final game: Knuckles was given a different palette, which uses yellow for his socks instead of green (and, oddly, pinker shades of red) plus in this particular scene the HUD isn't even drawn at all anymore.
Outside of the intro cutscene, this version of Knuckles can also be seen during gameplay, standing a short ways in front of the player at the beginning of Angel Island Act 1. He leaves after a few seconds of standing and gesturing. If the player walks forward before he leaves, he glitches out when the player gets near him. The exact way in which he glitches varies; if playing as Sonic, he turns blue due to the badnik palette loading over his, and if playing as Tails, he turns into a mass of incorrect tiles.
These Knuckles sprites, possibly before he was redrawn to be more in-style, are completely different from the other cutscene sprites used throughout the game.
Tails does not seem to spawn into the level for a while, aside from flying above the first badnik. The player can be airlifted by Tails, interestingly.
A fire shield and badnik right before the miniboss are missing.
Underwater countdown timer graphics do not load correctly.
In the debug list, there is a strange object that seems to test sprite scaling. It causes some very adverse effects on the game, its level collision, and its VRAM.
In one of the upper alcoves early in the level, there are 2 static monitors that hurt the player when broken. These were replaced with monitors containing Power Sneakers and 10 Rings in the final game.
The area before the miniboss has a few tiles incorrectly placed.
The miniboss cutscene is slower, rougher, and the miniboss plays a different sound when launching missiles.
The second part of Act 1 loads much more slowly, leading to some garbage object graphics at first.
The waterfall platform objects do not play any sounds.
Act 1's boss arena has the decorative flame objects like final, but they load incorrect graphics.
During the tunnel to the end of the level in Act 2, you can see for a moment when the flying ship graphics are loaded.
The HUD pauses for the entire duration the flying ship is present, and it resumes once it leaves. This was scrapped in the final because it also stalls the ring counter from refreshing, should the player get hit by the ship's bombs.
Eggman's "whooshing" sound when he goes through the trees at the end is completely different.
The sound that plays when Eggman burns the bridge is different.
The boss palette tends to cause issues with rings.
Even if you jump off the bridge while Knuckles destroys it, you still go to Hydrocity Zone anyway.
Angel Island Zone Act 1 Map
November 3rd
Final
Angel Island Zone Act 2 Map
November 3rd
Final
Unfinished cutscene
In addition to the surfboard cutscene, an early version of the final intro does exist in the prototype ROM, as shown in the embedded video. It can be enabled using the PAR codes 003CC6:0003 and 003CC8:5AD2. There are a few differences:
Some of the graphics are glitched.
The Tornado doesn't bob up and down while flying.
The final Knuckles object is present in addition to the prototype one. However, he doesn't jump up to uppercut Sonic (although it makes Sonic lose his super form), which softlocks the game because it leaves the player unable to move.
Hydrocity Zone
November 3rd
Level Select Icon
The background in Act 1 is completely different from the final game, featuring gray bricks and pillars, waterfalls, and rows upon rows of plant life. This early background design can still be seen in the level select icon for Hydrocity Zone in the final game.
Sonic and Tails do not play their falling animations when entering the level.
No animation plays for the fall into HCZ.
After dying, the background does not seem to load properly.
Game having problems with loading background at higher elevations after death in inner Hydrocity Zone.
The giant fan object does not play any sound.
When Sonic runs across water, there is no sound associated.
The Buggernauts use different graphics.
The grabbing hand booster object plays no sounds.
The Turbo Spikers play no sounds.
There are some misplaced spikes in Act 1.
Destroying a Blastoid causes the player to bounce back the other direction as if they hit a boss.
The 3D-like effect of the water doesn't work properly towards the middle of the level.
The Big Shaker's underwater palette is incorrect.
If Sonic is twirled around by the miniboss, he uses his death-animation instead of his floating animation.
When the miniboss enters, no sound is played.
The "whooshing" sound is played more frequently when the miniboss causes a whirlpool.
The drowning miniboss music bug exists in this prototype, but it plays IceCap Zone Act 2's track instead of the Sonic & Knuckles miniboss theme.
Turning super in either act, triggering the drowning music, and then leaving the water surface will instead play Mushroom Valley Act 2's track for until the super ability wears off.
Some walls in Act 2 use slightly different sprites during the wall crusher segment.
The wall crushing segment plays no sound.
Sonic will play his previous animation when jumping on a spinning cylinder.
Rings overlap tubes.
Layering issue with rings and tubes.
Knuckles is blue when first loading in.
The boss overwrites the water surface graphics.
Trapdoor objects have issues with sprite priority.
To do: Screenshot
There is a section in Act 2 involving a vertical bar object that is unused in the final game.
The Knuckles cutscene is very different and unfinished - he immediately charges towards Sonic upon seeing him, which in turn presses the button and makes the bridge collapse in under a second.
The small wall between the two also doesn't stop Knuckles from running, which results in him floating in air near Sonic.
The pathway to the boss has no objects.
Act 2's music has issues with volume.
After defeating the boss, the level music does not start back up.
In the final version, the level includes a couple of swinging balls and water droplet objects as eye candy. The proto lacks this, making the level look rather bland.
This ornamental tower only exists in the final version of Act 2.
Unused Chunks
Hydrocity Zone Act 1
ID DF A colorful mosaic? This is really too colorful to see in Hydrocity.
Hydrocity Zone Act 2
ID 28
Hydrocity Zone Act 1 Map
November 3rd
Final
Hydrocity Zone Act 2 Map
November 3rd
Final
Marble Garden Zone
To do: Object & Layout differences
The player doesn't start up in the sky.
The drillbot enemy seen throughout the level does not play any sounds when drilling.
Tails seems to be able to influence the spinning top object when both he and Sonic are on it.
The spinning top object doesn't fall out of the level when hitting a dead end.
The chain with spike ball object plays no sound.
The spinning wheel object makes no sound.
Neither Sonic nor Tails have animations for grabbing pulleys, instead continuing whatever animation they were playing before grabbing on.
The "switch" sound plays when grabbing the pulley.
There are some misplaced rings in Act 2.
It's possible to see below the level in Act 2.
When the player encounters the Act 2 boss, the background is buggy. The player also dies when they hit the bottom of the screen, so two-player Tails must be used to start the fight properly.
The game lags a lot during the Act 2 boss, and it's possible to stand on the air.
Like with Hydrocity Zone, there's no transition to Carnival Night Zone.
Marble Garden Zone Act 1 Map
November 3rd
Final
Marble Garden Zone Act 2 Map
November 3rd
Final
Carnival Night Zone
Act
November 3
Final
Sonic & Knuckles Collection
ACT1
ACT2
Both acts use a completely different music track. MIDI renditions of these songs would go on to be used for the same zone in Sonic & Knuckles Collection (although Act 1 is in a different key).
The Act 1 boss arena has no walls.
Once the Act 1 boss is beaten, there's no way to progress further without using the level select.
The underwater palette is very different, identical to the one seen in early screenshots.
Knuckles doesn't appear in Carnival Night Zone Act 2 at all, which results in the blackout and subsequent flood never happening, as well as Sonic falling to the ending area of Knuckles' Act 2. It is possible to get to the intended boss arena via Tails, though.
The capsule at the end of Act 2 is not present.
Touching one of the spinning cylinders as Tails will crash the game, possibly due to the game trying to load incorrect/missing graphics.
Carnival Night Zone Act 1 Map
November 3rd
Final
Carnival Night Zone Act 2 Map
November 3rd
Final
Flying Battery Zone
Act
November 3
Final
Sonic & Knuckles Collection
ACT1
ACT2
Flying Battery Zone is in a very preliminary state, lacking animated tiles and many objects.
November 3rd
Level Select Icon
The background is different, and matches the design seen in the zone's unused level icon. Oddly, the palette in the icon is a bit more blue. It additionally always uses the indoor background even in outdoor sections, and features "EGG" capsules not present in the final.
The background isn't set to loop and as a result, the background becomes more broken as you progress.
The Act 1 boss position matches that with Sonic the Hedgehog 3 Alone and Sonic 3C 0408.
Act 2's layout is even less complete.
The Barrier Eggman boss isn't in the level. Its object does exist within the data, though. The boss arena also exists, although the boss itself locks the screen much higher for some reason, possibly leftover from an earlier layout.
Act 2's boss position matches that with Sonic the Hedgehog 3 Alone.
Act transitions are once again not present.
There are color palette cycles listed for both Acts, but they are empty. Perhaps the lights in the background could have been intended to animate.
Unused Chunks
To do:
There is a lot of unused chunks left.
Chunks that were altered in 0408 onward.
The unused background chunks combined.
Meant for the background, this chunk is intended to combine with FD, F9, and F4. ID F3.
Meant for the background, this chunk is intended to combine with FD, F9, and F3. ID F4.
Meant for the background, this chunk is intended to combine with FD, F4, and F3. ID F9.
Meant for the background, this chunk is intended to combine with F9, F4, and F3. ID FD.
Flying Battery Zone Act 1
November 3rd
Sonic 3C 0408
Final (Sonic & Knuckles)
Flying Battery Zone Act 2
November 3rd
Sonic 3C 0408
Final (Sonic & Knuckles)
Flying Battery Zone Background
November 3rd
Final (Sonic & Knuckles)
IceCap Zone
To do: The prototype map of ICZ Act 1 needs a map.
Act
November 3
Final
Sonic & Knuckles Collection
ACT1
ACT2
Both acts use a completely different music track. MIDI renditions of these songs would go on to be used for the same zone in Sonic & Knuckles Collection. Act 1's appears to be unfinished at this point due to missing drums and a general lack of polish.
Sonic begins the stage running down the mountainside. In the final, he snowboards down it.
The "trap" glitch (in which the game treats the vertical screen wrap position as a bottomless pit under specific circumstances) affects both playable characters at this stage in development. The final version of the game fixed it for Sonic, but Tails would be stuck with it until Sonic the Hedgehog 3 & Knuckles.
There are some misplaced ice spikes in Act 2.
Though the tunnel leading to Launch Base Zone is present, the game does not actually send the player there like in the final game.
Both acts use a completely different music track. MIDI renditions of these songs would go on to be used for the same zone in Sonic & Knuckles Collection (although the MIDI version of Act 1 is in a slightly different key).
November 3rd
Final
The background has a different palette, resulting in a bluer ocean, a somewhat pink sky (not unlike Act 2) and a greenish Death Egg with darker supports. Much like Hydrocity Zone and Flying Battery Zone (initially), this palette would show up in the final game in Launch Base Zone's level select icon.
The player does not start by launching through the snow.
Knuckles' palette and sprites mess with some objects.
Some animated tiles are missing.
The building doesn't collapse, though the transition to the boss still works.
There are four warp tubes in the Twin Hammer boss arena, two on the floor and two on the ceiling. Entering a floor tube will warp the player to a corresponding ceiling tube.
The top of Act 2's background is buggy.
Jumping on the first floating platform encountered in Act 2 triggers a series of FM chirps. This can be found in a few other areas of the level. This does not seem to be found as a playable value in the sound test. Instead, this appears to be a bug related to jumping out of the water while only partially submerged.
Part of the first Act 2 boss is overlapping the foreground.
Knuckles stands on a bridge. The animated tiles also disappear for some reason.
After a certain point in the cutscene, Sonic freezes, making it impossible to beat the stage.
Water Level
Just like the final version, the water level is disabled, but intact. To activate it, follow the same directions as in the final version of Sonic 3.
Unlike the final version, these color palettes are greenish. The final version points to a copy of Launch Base Zone Act 2's palette. It would appear that water was intended for a much earlier layout, as the water levels do not match with the layout very well.
Launch Base Zone Act 1 Map
November 3rd
Final
Launch Base Zone Act 2 Map
November 3rd
Final
Mushroom Valley Zone
Act
November 3
Final
Sonic & Knuckles Collection
ACT1
ACT2
This zone has been mostly removed from the game at this point.
The level is titled "Mushroom Valley" in the level select. This early name is still used in the final game, but it was renamed Mushroom Hill in Sonic & Knuckles.
Reuses Launch Base Zone's title cards. This happens for the rest of the levels until The Doomsday Zone, with a few notable changes here and there.
As soon as you spawn in you die for no reason.
Early versions of the badniks exist, and can be placed in debug mode.
An early version of the Hey Ho miniboss is implemented.
A decompression error corrupts nearly all the graphics. A fix is provided below.
Uses Azure Lake's graphics and color palettes. Leftover palette data unique to this prototype exists, which is documented below.
An object layout is intact for both acts, but it doesn't fit the later Sonic 3C 0408 prototype Mushroom Hill Zone layouts.
Some unique background scrolling code is still intact.
Decompression Fixes
04A8D0:46EE - MVZ ACT1 decompression fix (Part 1)
04A8D4:46EE - MVZ ACT1 decompression fix (Part 2)
04A8E8:46EE - MVZ ACT2 decompression fix (Part 1)
04A8EC:46EE - MVZ ACT2 decompression fix (Part 2)
Unused Color Palettes
A re-imagining of how Mushroom Valley Zone may have looked. This screenshot is taken from the Sonic 3C 0408 prototype using this prototype's color palettes.
Unused color palettes can be found at offsets 0x1F2F0E, 0x1F582A for Act 1 and 0x1F2F6E, 0x1F588A for Act 2. These color palettes are identical for both acts and completely different from any of the palettes used for the final game. One color is wrong here, the brightest white, causing rings and the HUD to look incorrect.
Lava Reef is normally broken upon loading, but it's possible to make it playable by forcing the game to load leftover data from an earlier build, which just so happens to contain all of the necessary data for Act 1. The only data that is missing is collision.
The prototype contains a set of 6 identical maps for Act 1 and 1 map for Act 2, which both have differences, there are 7 complete maps and 2 identical map fragments. Unfortunately, no graphical data for Act 2 is present in the ROM.
Act 1 seems to be the most intact of the Sonic & Knuckles zones, having a full layout prepared for it, albeit completely lacking objects.
The level's palette is completely different from the final.
The pipes were completely redrawn and replaced in later builds.
The upper-right path was shrunk down in the final game.
Full Maps
0x1EB85E LRZ2
0x1EC4CE LRZ1
0x1ED2F6 LRZ1
0x1EE11E LRZ1
0x1EEF46 LRZ1
0x1EFD6E LRZ1
0x1F0B96 LRZ1
Fragmented Maps
0x1EAF4A LRZ1
0x1F3EC4 LRZ1
Color palettes
Act 1
Lava Reef Zone color palettes 0x1F58EA (act 1) and 0x1F59AA (act 2).
Act 2
A color palette for Lava Reef Act 2 is located at 0x1F594A or 0x1F302E. This color palette does not match well with any known version of Lava Reef Act 2. However, a few of the colors are recognizable to the final version, albeit arranged very differently.
Background
Act 1 Background
November 3rd
Final (Sonic & Knuckles)
(Background, Map Rips: evilhamwizard)
The lava channels, the far-end cavern hollow background, and the Death Egg were redrawn. The coloration is also more blue-green in the prototype.
The HUD uses an incorrect palette here. The second palette line apparently has not been defined and is only using a single color in place of white.
Unused Chunk
Lava Reef 1
Only a single chunk is not used to compose the map. ID 7E.
Lava Reef 2
Although the map contains several unused chunks, these may have been used for the boss area.
1D, 1E, 32, 82, 86, 99, A8, A9, AA, AB, AC, AD, AE, AF, B0, B1, B2, B3, B4, B5, B8, D4, D5
D6, D7, D8, D9, DA, DB, DC, DD, DE, DF, F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, FA, FB, FC, FD, FE, FF.
Lava Reef Zone Act 1 Map
November 3rd
Sonic 3C 0408
Final (Sonic & Knuckles)
Lava Reef Zone Act 2 Map
November 3rd using S&K dataset and palette, with chunk IDs shifted / remapped
Sonic 3C 0408
Final (Sonic & Knuckles)
Sky Sanctuary Zone
November 3
Final
Sonic & Knuckles Collection
While the title card reuses Launch Base Zone's, it also happens to be missing the act numbers. This seems to indicate that the rest of the S&K zones had proper title cards at one point.
The music instrumentation here is quite different.
Act 2 oddly uses Death Egg Zone Act 1's music. This is likely the result of the Death Egg's track being right after Sky Sanctuary's.
Death Egg Zone
The music is almost identical to the final.
Both acts use Death Egg Zone Act 2's music.
The Doomsday Zone
November 3
Final
Sonic & Knuckles Collection
Much like Sky Sanctuary Zone, the act numbers are missing from The Doomsday's title cards. It still claims to be Launch Base Zone, though.
The music here has different instrumentation on a few parts.
Zone ID $0D
This zone lacks a title card, in the final version of Sonic the Hedgehog 3 it simply said "Zone".
The Blue Spheres special stage music is used here.
Act 1 uses AIZ intro graphics, whereas in the final it uses the standard level graphics.
Azure Lake
There is a spring that was removed from the final.
Balloon Park
November 3
Final
Sonic & Knuckles Collection
The music is composed differently.
Desert Palace
November 3
Final
Sonic & Knuckles Collection
One of the background palette's colors is incorrectly set to black instead of brown.
The music here is also composed differently.
Chrome Gadget
November 3
Final
Sonic & Knuckles Collection
The background scrolls differently.
The music here is also composed differently.
Endless Mine
The large breakable gold nuggets aren't there.
The music is almost exactly the same.
Zone ID $16
Act 1 was later used for Lava Reef Act 3 or Lava Reef's boss.
Act 2 was later used for Hidden Palace Zone.
Act 2 has a bug that causes the Launch Base Zone Death Egg graphics to load midway through the level The same glitch still exists in the final version of Sonic 3 when accessing Zone 16, and a similar glitch can be pulled off in Sonic 3 & Knuckles's Hidden Palace zone using a debug mode glitch seen in this video here: https://youtu.be/NxKYgaM50B8
Both acts play the Special Stage music.
There is no title card.
Zone ID $17
Act 1 was later used for Death Egg Zone's boss.
Act 2 was used for the alternate Hidden Palace Zone that is accessed through a big ring in Sonic & Knuckles.
Both acts use the special stage music.
There is no title card.
Gumball Machine
Incredibly bare bones at this point in development, but a start has been made.
Plays the Special Stage theme.
The map only features a layout - there's no collision detection for the walls, the gumball machine itself doesn't do anything, and most importantly, there aren't any bumpers, meaning you unceremoniously fall... to your death, as the code to end the bonus game isn't present. The tiles for the spring net are present(!) and are even a different color(!!), but alas, there's no springs atop them, nor does said net have any collision itself.
There's some different graphics, namely in the tileset for the walls - the final has more shading details. The background is filled with placeholder tiles instead of the finalized checkerboard, and the layer in front of it is quite different in design. The gumball machine itself is more or less finalized, however.
This level lacks a Bonus Stage title card.
The HUD still has SCORE and TIME listed, unlike the final version of Sonic the Hedgehog 3.
Glowing Spheres
Even less complete than the Sonic 3C 0408 prototype.
The stage's background does not exist in the ROM, and instead uses placeholder number tiles. These numbered tiles are intended to be animated by a seemingly not yet present reloading routine.
The Bonus Stage title card is missing.
The HUD still has SCORE and TIME listed, unlike the final version of Sonic the Hedgehog 3.
Slot Machine
The Bonus Stage title card is still missing.
The HUD still has SCORE and TIME listed, unlike the final version of Sonic the Hedgehog 3.
Background graphics with animations
November 3rd
Final
The slot machine in the November prototype is quite bare-bones, lacking several details that would appear in the final game.
The simple hole that operates the slot machine was replaced with an elaborate glass cage.
A bunch of shading was added to the blue area, as well as connections between the shapes and the central cage. The top shapes were shifted down to accommodate the top-most shade.
On the topic of the squares and triangles, they had their colors changed to a cycling yellow palette.
The indigo color used by the slot machine was updated to a proper blue.
The protoype's second palette is missing the colors needed for Rings, which is obviously a problem. The colors in the object palettes had to be shuffled around to accommodate both the Rings and the updated slot machine...
November 3rd
Final
...which would result in the slots themselves losing some of their details.
A layout is present, but collision has not been implemented.
Unused Chunks
Some unused chunks exist, most of which are blank, but some appear to be laid out to test the background animations. Blank chunks include: C, D, E, F, 2A, 2B, 2C, 2D, 2E, 2F, 34, 35, 36, 37, 38, 39, 3A, 3B, 3C, 3D, 3E, 3F, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 4A, 4B, 4C, 4D, 4E.
01
02
03
04
05
06
07
08
09
0A
0B
4F
Special Stage 1
The Special Stages are tech demos at this point in development, using different sprites entirely for the spheres. No proper gameplay has been implemented however, other than manipulating the spheres. Holding A and pressing Start will return you to the Title Screen.
Special Stage 1 features a pre-rendered gray sphere, with red spheres rotating around it. These set of spheres do remain in the final game in Angel Island Zone Act 1, however they are unused.
Button
Control Pad 1
Control Pad 2
Start
Toggles between automatic and manual rotation.
Toggles between automatic and manual rotation.
A/C
Rotates left or right.
Zooms the spheres in or out. A zooms out, C zooms in.
B
Resets the spheres to their point of origin.
If automatic movement is enabled, stops the spheres from rotating along one of the axes if held down.
Up/Down
Adjusts how fast the spheres rotate on one of the axes.
Moves the matrix up and down.
Left/Right
Rotates the spheres along the Y-axis
Moves the matrix up and down.
Special Stage 2
Special Stage 2 features a flat square of spheres bouncing up and down while rotating. A secondary animation causes them to contract and expand. Parts of this animation overload the VDP's sprite bandwidth, causing some of the sprite pixels to disappear (as can be seen in the expanding animation below).
Button
Control Pad 1
Control Pad 2
Start
Toggles between automatic and manual rotation.
Toggles between automatic and manual rotation.
A/C
Speeds up or slows down the rotation when automatic, or rotates the spheres left or right along the X-axis when manual.
Zooms the spheres in or out. A zooms out, C zooms in.
B
Toggles between the primary and secondary animations.
If automatic movement is enabled, stops the spheres from rotating if held down.
_AIZ1.png)
_HCZ1.png)
_MGZ1.png)
_CNZ1.png)
_FBZ1.png)
_ICZ1.png)
_LBZ1.png)
_LBZ1_UnderwaterPal.png){kind=small}
_LBZ1_Underwater.png)
_MVZ1.png)
_MVZ_Sonic_3C_Proto_0408.png)
_MVZ_Pallete.png){kind=small}
_SOZ1.png)
LRZ1restored.png)
_LavaReefAct2palette.png){kind=small}
-magic-hand.png)
_SSZ1.png)
_DEZ1.png)
_DDZ1.png)
_Zone0D.png)
_ALZ1.png)
_BPZ1.png)
_DPZ.png)
_CGZ.png)
_EMZ1.png)
_HPZ1.png)
_DEZ3.png)
_GlowingSpheresBonus.png)
_SlotMachineBonus.png)
