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Proto:Sonic the Hedgehog 2 (Genesis)/Simon Wai Prototype

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This is a sub-page of Proto:Sonic the Hedgehog 2 (Genesis).
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Sprite Changes
Download.png Download Sonic the Hedgehog 2 (Simon Wai prototype)
File: Sonic The Hedgehog 2 (Simon Wai Prototype).bin (1 MB) (info)

The Simon Wai prototype of Sonic the Hedgehog 2 is definitely further along than the Nick Arcade prototype, but there are still quite a few unfinished elements such as level layouts and things that have not been fully implemented. There are also many, many unused graphics that can be found via hacking. In addition, there are a few levels not seen in the final, but most of them contain nothing.

The prototype is named after Simon Wai, who found it on a Chinese Geocities page in 1998. The actual ROM image likely came from a demonstration cart that was stolen from a New York toy fair in 1992, then dumped.

General Notes

  • The SEGA logo does not appear when booting up the game. However, if you get a Game Over, the game does show the SEGA logo and then shows the title screen. This also happens if you stay on the title screen and allow the resulting demo to run its course. The sound is also noticeably higher pitched than in the final.
  • Uses the earlier title screen and lacks the title menu.
  • Any zone with water will be glitched when playing in two-player mode, as the game loads the graphics incorrectly.
  • Special Stages are still not present, although the music is.
  • Locking on this prototype with Sonic & Knuckles will unlock the full Blue Sphere game, as it does with the Nick Arcade build. This is because the two prototypes have the same serial code as Sonic the Hedgehog (REV01), which determines the result of the lock-on.
  • Rolling demo gameplay is the same as the Nick Arcade build, and has not yet been rerecorded to fit subsequent layout changes.
  • The level select has the same general appearance as the level select from Sonic 1.
  • Special Stage cannot be selected on the level select, as they don't exist yet.
  • There are no checkpoints in the game. One can be placed via Debug Mode, where it can be seen that they have a totally different design to the one used in the final game.
  • The player starts most Acts positioned slightly more to the left than they do in the final game. However, this doesn't affect all levels.

Cheat Codes

Sonic2SimonWai LevelSelect.png
  • Level Select - A + Start.
  • "Night Mode" - C + Start.
    • Unlike the final game, Debug mode doesn't need to be active for this to work.
  • Two-Player Mode - on the level select, press B + Start on any level that doesn't have water.
  • Debug Mode - C, C, Up, Down, Down, Down, Down, Up.
    • You can also enable it through the patch code FFFFFA:0001. The ring sound will play even if the C button is never pressed, but nothing else happens.
    • Layer switches are visible in this version's debug mode. A checkpoint sound is made whenever the player (or Tails) passes through them.
    • Tails jumps to Sonic's position when leaving Object Placement mode.


  • At this point, Tails is still quasi-independent.
    • The second player is able to control Tails, except Tails will also follow Sonic.
    • Tails cannot complete a level on his own, since the game only loads the goal sign when Sonic approaches it.
    • The AI is much simpler; it only follows Sonic and does not try to keep up.
    • Tails loses the player's rings when he is hit.
    • If he dies, he drops back in from the top of the screen and immediately goes into a roll when he hits the ground because he can't fly yet.
  • If player one completes a level, Tails can be controlled if Sonic is off-screen.
  • As with the Nick Arcade build, the spin dash is still a work-in-progress, as Sonic and Tails can only charge it up once; the sound for when Sonic spins in Sonic the Hedgehog is still heard due to there not yet being a specific sound effect for the spin dash.
  • As with the Nick Arcade build, the timer resets to 9:00 when it approaches 9:59 in order to allow the player to test the stages for extended periods of time.
  • The screen doesn't scroll up or down when you look up or down for a certain period of time.
  • Bubbles are loaded incorrectly from the VRAM.
  • A unique bug is present in this prototype. Upon collecting 100 rings, the game will play the Death Egg Zone music instead of the usual 1-up sound. This is because sound bank 88 (which was the 1-up sound in the Nick Arcade build) has since been overwritten and not edited to play the correct sound. Game Genie code XCOT-AAC4 will cause the correct tune to play. The monitors, on the other hand, were programmed with the correct 1-up sound.
  • The underwater countdown music uses the level select theme. When Sonic gets out of the water, the Emerald Hill music begins.
  • Spike behavior is the same as the first game - getting hit does not give the player invincibility frames to avoid being immediately hurt from other spikes.
  • Rolling tubes do not force the player to roll, notably in Hill Top and Hidden Palace.
  • Speed Shoes do not increase the speed of the music.
  • No title cards or score tallies appear at the beginning and end of an Act respectively. However, the clear theme does play in the case of the latter.
  • The splashing animation is corrupted, showing misaligned bubbles instead of a splashing sprite. Tails has no splashing effects.
  • 2 Player mode only has split screen for Sonic and Tails. Otherwise, it's identical to 1 Player mode - The level will still restart if Sonic dies.
  • Aquatic Ruin, Chemical Plant, Hill Top and Emerald Hill are the only zones where signposts appear. Capsules do not exist yet.


Without accessing the level select, the game allows you to play Aquatic Ruin, Chemical Plant, Hill Top, and Emerald Hill. After beating the Emerald Hill boss, the game resets to the Sonic the Hedgehog SEGA screen despite being disabled from appearing at startup.

Internal Zone Order

Zones that are either placeholders or leftover from a previous build are in italics, new levels are bold, and moved level slots are blue.

Sonic 1 Nick Arcade Simon Wai Final
00 Green Hill Green Hill Emerald Hill Emerald Hill
01 Labyrinth Labyrinth leftovers
02 Marble Chemical Plant Wood Wood leftovers
03 Star Light Emerald Hill
04 Spring Yard Hidden Palace Metropolis Metropolis
05 Scrap Brain Hill Top Metropolis 3 Metropolis 3
06 Wing Fortress
07 Hill Top Hill Top
08 Hidden Palace Hidden Palace
0A Oil Ocean Oil Ocean
0B Mystic Cave Mystic Cave
0C Casino Night Casino Night
0D Chemical Plant Chemical Plant
0E Genocide City Death Egg
0F Aquatic Ruin Aquatic Ruin
10 Death Egg Sky Chase

Neo Green Hill Zone (Aquatic Ruin)


Most of the underwater sections are missing entirely in this version. Instead, there's just a lot of bottomless pits.

  • Player starts slightly more to the left in both Acts.
  • Grounder holes can be spotted throughout the level, albeit empty.
  • Floating platforms cause an "anti-gravity" bug if you jump off of them at the last possible moment (after they fall off the bottom of the screen and despawn).
  • The only enemies present are the arrow-shooting Robotnik-face totems.
  • The column objects are missing, but they can be found and placed via debug mode.
  • The background is missing the half used for underwater sections.
  • The leaves at the top of the stage scroll vertically and do not drop leaves or make sounds when walked through.
  • The bottom of the stage is much higher up.

Act 1

  • Due to the lack of water sections, the last pool before the goal is slightly different.

Act 2

  • Act 2 has no boss.
  • There are more columns in the boss arena. Despite this, the area is inaccessible due to the goal area being just before it.

Chemical Plant Zone


Mostly the same as the final.

  • Player starts slightly more to the left in both Acts.
  • The loops have slanted corners instead of 90-degree corners, as in the Nick Arcade build.
Proto Final
Sonic2WaiProto CPZLoop.png Sonic2 CPZLoop.png
  • The background girders are grey.
  • The platforms which move across rails are much smaller.
  • It's possible to fall out of some of the automated pipes.
  • The blue bubbles that jump between tubes make a different sound effect.
  • The small horizontal platforms that the player uses to cross water in Act 2 are shorter.

Act 1

  • A backwards boost panel is missing from the bottom route.
  • Some ledges are missing above a set of two loops halfway through the level.

Act 2

  • The map is shorter due to the lack of a boss.
  • The area below a long moving platform segment at the bottom of Act 2 is empty. In the final, there are ledges below this part in order to make the platforming less tedious.
  • In the top path, an extra ceiling ramp was placed in the final that sends the player backwards if they run too fast.
  • 3 Monitors are missing above the goal area.

Hill Top Zone

Down you go.

The level layout has been worked on somewhat since the Nick Arcade build, but is still different from the final.

  • Player starts slightly more to the left than in the final.
  • Moving platforms do not make any sounds.
  • The only breakable rocks are the ones above tunnels in Act 2.
  • Sonic doesn't automatically spin when going through tunnels.
  • Earthquakes are silent.

Act 1

  • The beginning of the level flat, whereas in the final there's a small ramp.
  • The first lava pit in is slightly higher than in the final.
  • The wall above the first S-tube only has one passage rather than two. The ledge to the left of this wall is also a lot higher than it is in the final.
  • The lava pit near the first S-tube is slightly more to the left. In fact, the bottom of this pit still remains in the final game!
  • A large wall with two seesaws in the middle of the level is higher in this version. The yellow spring at the third section of this wall in the final isn't in this version due to it being high enough to jump to the top at that point.
  • The ascending floor starts ascending sooner than it does in the final - in fact, it does so before the player passes through the entrance to the area, making it possible to get stuck if they don't jump into the area in time.
  • An extra lava pit can be found below the second moving swing that was removed in the final.
  • The signpost is positioned slightly further to the left than it is in the final.

Act 2

  • The beginning has a seesaw and a lava pit. In the final, there's just a large ramped wall.
  • A seesaw is present where the level splits into two paths. It was replaced with a rock, a platform and a lava pit in the final.
  • The first S-loop slightly more to the right in this version.
  • A red spring and a short passage can be found in the top path. In the final, the spring was replaced with a seesaw and the passage was removed due to the size of the ledge containing it being reduced.
  • Early in the bottom path are 3 small lava pits and one large one. In the final, the smaller pits were replaced by a ramped wall while the larger one was made slightly smaller and raised higher.
  • A shield box was added just before the third moving swing in the bottom path. The lava pit below the swing was given a rising platform as a means of escaping - something not possible in this version.
  • The room with rising lava is missing some platforms.
  • The downhill area just after the rising lava room consists entirely of blocky ledges in this version.
  • If the player takes the top path and passes the area with the rising floor, they encounter a large lava pit. In the final, this lava pit was removed and replaced by a seesaw.
  • Act 2 ends far earlier than it does in the final game. In fact, there's two signposts for the upper and lower paths.
  • Act 2 is entirely missing the area where the last checkpoint and boss appear in the final.
  • The ledge where the upper signpost appears was changed to a ramp in the final.

Green Hill Zone (Emerald Hill)


The most complete zone in the prototype. However, it still manages to be very different from the final game.

  • This and Hidden Palace are the only Zones in this prototype that contain badniks.
  • A snail-type badnik appears here, like in the previous build. It charges when the player approaches it.
  • Coconuts has not been implemented yet.
  • At one point, there is a hidden wall which is supposed to contain an extra life; it does, but it is blocked off. The only way in is by staying on the falling platform.

Act 1

  • A floating ledge is missing before the first loop in Act 1.
  • The long passage in Act 1 has less 'windows' than it does in the final.

Act 2

  • Player starts slightly more to the left.
  • Some floating ledges above the first set of loops are missing.


  • As with the previous build, this Zone contains the only boss you can fight. However, the machine does not explode when destroyed, even though the Sonic the Hedgehog explosion graphics are still present in the ROM.
  • Eggman's vehicle is already parked on the spot instead of entering from the right.
  • The boss music starts much earlier - as soon as the player reaches the area where the last checkpoint is in the final.
  • The scroll locks twice - once at the point the boss music starts playing and again at the boss arena.
  • The boss travels much further to the left off screen than it does in the final. It actually travels to the point of the first scroll lock, and can be observed doing this if the player waits long enough in that spot for the boss to appear.
  • The boss vehicle is waiting for the player at the arena, rather than coming in from the right.
  • Robotnik flies down vertically rather than diagonally into the vehicle. His propeller doesn't make any sounds either.
  • Robotnik doesn't react to doing damage, being hit or defeated.
  • The player is bounced less when the boss is hit.
  • There are no explosion effects when the boss is defeated. Despite this, the explosion effects from Sonic 1 can be found in the game.
  • When the boss is defeated, its wheels do not fly off all at once. Robotnik also retreats faster than he does in the final.
  • If defeated outside the arena (so the game doesn't automatically reset), the boss vehicle disappears a certain amount of time after defeating it. If an object is placed using debug mode afterwards, Robotnik will appear and "ride" the object as if it were the vehicle.

Oil Ocean Zone


This zone has more changes made to the layout than any other. In general, these changes were made to make the zone longer.

  • Player starts slightly more to the left in Act 2.
  • The music is what would eventually become the final's 2P VS version of Casino Night, even though the normal Oil Ocean theme is present in the sound test.
  • The palette cycle is reversed, making it look like the sewers are sucking up the oil.
  • The sun does not animate or scroll.
  • There are fewer collapsing ledges.
  • The oil splashing animation is missing, and oil slides have no effect on Sonic.
  • Elevators are smaller than in the final, making them more difficult to stand on.
  • A mechanic is present which features a rolling checkered ball (like the scrapped ball in Sonic the Hedgehog) that springs up and rolls along when a button is pressed. While cut from the final, it can be placed in debug.
  • The valves that shoot their tops into the air do not make sounds or have fire in this version. If the player stands under an open one, they won't get hurt either (though they can be crushed)
Proto Final
Sonic2WaiProto BGOOZ.png Sonic2-OOZBG.png
  • The background scrolls as a whole rather than using individual layers. This means the sun in the sky does not stay in the same position throughout the level like it does in the final. It's also not animated at all.
  • There are two large pipes in the background that aren't in the final game.
  • As the scrolling features of the background are not implemented yet, the extra part of the background that goes unseen in the final appears normally in this version.

Act 1

  • Act 1 is completely playable, albeit with no signpost at the end. Many objects present in the final are missing, making it much harder to play through.
  • An extra upper path is present in the first half of Act 1 that was removed in the final.
  • There are more oil slides in this version.

Act 2

  • Act 2 cannot be played more than a few seconds in without debug or glitching, and the level layout is very different from the final.
  • The map was extended in the final to accommodate the boss.
  • The leftmost part of the upper area of Act 2 is further to the left than it is in the final. One of the chunks from this early layout is still there in the final floating in the air.
  • The middle of Act 2 - particularly the higher route is much different to the final game's version.

Metropolis Zone

This is, also, not technological.
  • None of the acts in this level loop vertically or have layouts that do so.
  • The pistons take longer to pop out of the ground, and they don't launch Sonic very high. In fact, this causes the player to become stuck at a certain point in Act 1. The damage from standing adjescent to one is very delayed too.
  • The screws and metal crushers can only crush Sonic if he is below them. If he is on top of them, he will simply be shoved into the ceiling.
  • Rotating nets are animated, but only one of them (longer one in the bottom part of Act 1) has the object to make them function - the player just falls through the others.
  • The corkscrews will not stop turning, meaning the player can potentially go as high as s/he wants.
  • A parallelogram-shaped machine that moves horizontally and diagonally through narrow corridors appears in Act 3.
  • You cannot complete any of the Acts. The first two Acts have no goal sign and cut off with you dropping into a pit, while the third Act ends with a platform ride into emptiness.
Proto Final
Sonic2WaiProto BGMZ.png Sonic2 BGMZ.png
  • The background uses an orange palette instead of a blue-gray one.
  • The background is larger than the one in the final game.

Act 1

  • Crushers are present at the beginning of the level. In the final, they were replaced by a rotating net.

Act 2

  • Lava does not hurt the player.
  • Many of the floors in the level are inclined differently in this version.
  • Rotating nets were added to Acts 2 and 3 in the final game. In this version, only Act 1 has them.
  • Acts 2 and 3 have more rotating cogs. Some of the ones in Act 2 appear partially inside floors and walls.
  • The second half of Act 2 was revised for the final, extending it slightly.

Act 3

  • Includes a diagonal moving platform object that isn't in the final game.
  • Due to the moving platform, Act 3 contains many diagonal spaces for them that were completely removed in the final. This is easily noticed in the first half of the act, which was revised heavily after the platform's removal.
  • The end of the level has more speed tubes and uses a different route than the final game. In the final game, the tubes were replaced with a screw to take advantage of the vertical loop.

Dust Hill Zone (Mystic Cave)


Both Acts use somewhat different level layouts from the final, but have few or no objects and no rings.

  • The bridge object works in Act 1, but uses a switch to open instead of vines seen in later builds.
  • Act 2 is completely devoid of objects.
  • There is no signpost/boss/capsule in either Act, making them both unable to be completed.
  • The name of this Zone is misleading, and most likely left over from an older build.
  • A number of flat ledges were changed to ramps for the final game.

Act 1

  • It seems Act 1 was only used for object testing, as the first half has a bunch of randomly placed objects and the other half is empty.The objects include:
    • Falling platforms
    • Swinging platforms
    • Moving spiked walls
    • Spiked balls rotating around a block.
    • Spiked platform that swings when the player passes under it.
    • Rocks that crush the player.
    • Moving Wooden Boxes
    • Invisible walls
    • Openable bridge (In this version, it's activated by pressing a switch rather than holding a vine.)

Act 2

  • Ceilings were added in Act 2 to make it a completely enclosed space.
  • An entire upper route in Act 2 was removed.

Casino Night Zone

Sonic in Vegas!

This zone has a completely different look, with a pink card-suit-based scheme and sky blue floors.

  • Player starts in the air and slightly more to the left.
  • Tile layout is pretty similar to the final, but many level pieces are broken or missing; as such, both Acts are impossible to play without debug.
  • Act 2 has a screwed-up background, since it is accidentally overwritten with the pinball table graphics.
  • There are no objects or enemies, and debug mode only has the default Ring / Static Monitor.
  • Due missing the object that makes them function, all of the bumpers in the level do not work.
  • Many of the flipping tiles are missing, or the outlines flash and the tiles remain stationary. Identical tiles are used to mark hidden passages and appear normally, but those ones don't flip.
  • There are no Sonic, Miles, or Casino tiles. Instead, these are part of the layout tiles themselves.
  • There are many solid black areas in the Zone tiles that should be transparent.
  • There is a different sound for the bouncers that give points and disappear after three hits (and don't yet exist).
  • The red bumpers that give 10 points per hit do not exist. If the object (obj44) is placed in the level, it instead places a solid wall similar to the one from Green Hill Zone, indicating a leftover from the Nick Arcade build.
  • Conveyor belts can be found, but do not work.
  • The player cannot run up any walls in this zone.
  • There are a lot of collision bugs in this zone.
  • Loops do not work properly due to the lack of layer switches.
Proto Final
Sonic2WaiProto BGCNZ.png Sonic2 BGCNZ.png
  • Along with the rest of the zone, the background is entirely different to the one seen in the final.
Proto Final
Sonic2WaiProto SLOTMACHINE.png Sonic2 SLOTMACHINE.png
  • It is possible to visualize an unused level chunk in what would be an early version of Slot Machine.

Act 1

  • The four rounder, smaller pinball backgrounds with slots in them are missing from Act 1.
  • The first half pipe area at the beginning of Act 1 incorrectly uses two left sides.
  • There is a large pit in the bottom route of Act 1 that was removed in the final.
  • An area in the top route of Act 1 with many small, square platforms is present that was completely removed in the final.
  • Fewer bumpers are present in the bottom route of Act 1.

Act 2

  • The entirity of Act 2's layout is shifted one chunk to the right due to an extra piece at the start.
  • Act 2's map is shorter due to the lack of a boss.
  • Aside from the last two, the pinball table backgrounds in Act 2 are in different locations.
  • The last two pinball table backgrounds in Act 2 are very rough and much bigger. The walls in the area around both of them are also very different, lacking many of the slopes and bumpers present in the final game.
  • There is a second, higher goal area in Act 2 that was completely removed in the final game.

Wood Zone

Does this level look flat to you?

A scrapped Zone. It seems that only a small portion was ever implemented and did not get too far.

  • What exists of the level quickly ends because of a ramp that has a platform blocking the top of it, which is impossible to get past without debug.
  • Plays the music for Metropolis Zone.
  • If you use debug, you can move upwards in the level and find a conveyor belt, but it doesn't work.
  • Level collision is glitchy.
  • Unlike any other zone in the game, the entire background is located under the stage instead of in the background layer.
  • Act 2 is empty, containing nothing but Sonic and Tails falling to their deaths.

Hidden Palace Zone

It took them 21 years, but they finally finished it.

This zone has very few changes from the previous version. For more information, see the Nick Arcade prototype page.

  • This Zone has had mainly minor behind-the-scenes changes since the Nick Arcade build.
  • Sonic and Tails have had their underwater palette updated.
  • The music has been changed to what would be the 2P VS version of Mystic Cave in the final.
  • The debug list has had a face lift, and all the unused objects that were in the Nick Arcade build are now gone. The items that are still there have fixed previews.
  • The collision bug caused by spindashing into the big emerald from far away has been fixed.
  • The art for Emerald Hill's enemies is no longer loaded in this Zone.
  • This and Emerald Hill are the only Zones in this build with badniks in it.


Genocide City Zone

What are you?
  • Both Acts use Chemical Plant's music, Emerald Hill's palette, and the default Ring / Static Monitor objects in debug mode. They're also completely empty.

This Zone was originally designed as a single-act mechanical-themed area. It is called "Genocide City" in this build because of an average understanding of English by the person who originally named it, then changed to Cyber City after this prototype. Before the team started putting it in the game, it was scrapped; the level design was used for Metropolis Act 3, while the graphics were used in Level 3 of Sonic Spinball (The Machine).

Death Egg Zone

  • Both Acts use Emerald Hill's palette, but play no music and are empty. Dying here causes all sound to cut off.

Zone ID 01

Sonic2gen waiproto GHZRemains.PNG
  • Uses Emerald Hill's palette and music, complete with a lack of debug mode objects aside from the ring and Static Monitor.

This empty stage slot can be accessed by entering Game Genie code AA7A-ACGY or Pro Action Replay code FFFE10:0100 and choosing Green Hill Zone Stage 0. As with Genocide City, Death Egg, and Wood Zone Act 2, Sonic and Tails immediately fall to their deaths upon entering. Presumably, this stage belonged to the original Labyrinth Zone, which was featured in the Nick Arcade prototype. In that prototype, the level was just garbage data.

Zone ID 03

Sonic2gen waiproto DHZBetaLeftovers.PNG
  • Uses the final Oil Ocean theme, and only has the default Ring and Static monitor objects in debug mode.

This empty stage slot can be accessed by entering Game Genie code AA7A-AGGY or Pro Action Replay code FFFE10:0300 and choosing "Green Hill Zone Stage 0" on the stage select. Like Genocide City and Death Egg, this stage uses Emerald Hill's palette and is entirely empty, causing Sonic and Tails to immediately fall to their deaths upon entering. In the Nick Arcade prototype, this slot was used for Emerald Hill Zone. Presumably, this slot was meant for Dust Hill.

Zone ID 06

Sonic2gen waiproto WFZSlot.PNG
  • Contains a pitch black background, uses what would become the two-player Emerald Hill Zone theme in the final, and only has default Ring and Static monitor objects in debug mode.

This is an empty stage slot that can be accessed by entering the Game Genie code AA7A-ANGY or Pro Action Replay code FFFE10:0600 and choosing "Green Hill Stage 0" on the stage select. As with the others, the stage is entirely empty, prompting Sonic and Tails to fall to their immediate deaths upon entering. Presumably, this is the level slot that would later on become the Wing Fortress Zone.

Zone ID 09

Sonic2gen waiproto SCZSlot.PNG
  • Uses the Emerald Hill Zone palette, the Sky Chase Zone theme as its default background music, and only has default Ring and Static monitor objects in debug mode.

By entering Game Genie code AA7A-AWGY or Pro Action Replay code FFFE10:0900 and choosing "Green Hill Stage 0" on the stage select, the player will be taken to yet another empty Zone that promptly causes Sonic and Tails to fall to their deaths. Presumably, this was the original level slot of Sky Chase Zone, before it took Death Egg Zone's old slot at 10.


The tracks for the final's invincibility, drowning, ending, song #10, and credits themes are all nonexistent while the continue, game over, extra life, and Chaos Emerald fanfares are already in their final form. Everything else, however, is at least slightly different.

Audio Name Notes
Title Screen The title screen still uses the original theme from Sonic the Hedgehog.
Stage Select/Drowning The snare sample has been replaced with a kick, and the trumpet sample is heavier. A backing trumpet in the left channel is instead a celesta. The right channel has an extra bottle-like instrument.
Neo Green Hill Zone (Aquatic Ruin Zone) The instrumentation is heavier and lacks a backing part in the left channel.
Chemical Plant Zone/Genocide City Zone About 1.4% slower than the final, and the first pitch bend before the loop comes in late.
Hill Top Zone About 11.35% slower.
Green Hill Zone (Emerald Hill Zone) About .3% slower, and some of the percussion is more distinct.
Wood Zone/Metropolis Zone About 1.6% faster. The instrumentation is radically different, with more grating and off-key tones. Also uses a different off-beat sample, and the melody has a simpler, downward pitch bend.
Hidden Palace Zone (Mystic Cave 2-Player) About .6% faster. The intro has more quavery instruments, and the mix is overall less full.
Oil Ocean Zone (Casino Night 2-Player) About 10.75% slower.
Zone ID 03 (Oil Ocean Zone) About 8.35% slower. Has more distinctive intro instrumentation, and some backing instrument samples are slightly different.
Dust Hill Zone (Mystic Cave Zone) About 6.6% slower.
Casino Night Zone About 12.93% slower. The instrumentation is much different, giving a sleazier feel. The percussion and bass are much more ornamented. The prototype has an extra harmony line just before the loop.
Zone ID 09 (Sky Chase Zone) About 6.95% slower, and has a louder bell sample.
Unused (Wing Fortress Zone) About 6.23% slower. The backing instruments are slightly altered and much louder, sometimes to the point of almost drowning out the melody.
"100 Rings" Extra Life (Death Egg Zone) About 15.65% faster, and has much fainter and sicklier instrumentation. The percussion is also very different.
Act Complete Seems to have a very slight jump in the first two notes that the final doesn't.
Dr. Robotnik About .25% slower. Has a much heavier mix, and a faint additional backing part.
Unused (Final Boss) About 1% slower. Has a different, less distinct kick sample.
Invincibility (Super Sonic) About 7.4% slower. The right channel has an extra "alarm" instrument in the intro. This was later replaced with a different theme and became the music for Super Sonic.
Unused (2-Player Results) About 1.5% slower.
Zone ID 06 (Emerald Hill 2-Player) About 6.64% slower. Has a slightly shorter kick sample.
Unused (Special Stage) Has a very slightly more prominent kick sample.

Unused Sprites

To do:
Drill + Chiki Chiki Boys Leftovers
Sprite Name Description
Spring Monitor icon This is always loaded in the VRAM in the levels, but you never actually see it. Presumably, it would have worked like the Pogo Spring monitor in Sonic Triple Trouble. This was also in the Nick Arcade build.
Sonic getting up An unused sprite that had no known purpose until the earlier Nick Arcade build was released, in which Sonic recoils in this manner when colliding with a wall. At this point in development, the recoil mechanism has been removed and only their sprites are left. The sprite on the right survived into the final and is used when getting up after Sonic has sat down from impatience, but the sprite on the left has been overwritten.
Sonic2proto LookingAtYou.png
Sonic facing the player Unused sprites of Sonic turning to face the player directly. Similar sprites are present and used in Sonic 3 for when Sonic interacts with certain obstacles, such as the spinning cylinders in Hydrocity.
Spr ledge.gif
Sonic on a ledge An unused animation of Sonic balancing on a ledge. Looks similar to an animation used for the same purpose in Sonic 3.
Sonic2Beta SonicPull.gif
Sonic pulling something An unused animation of Sonic pulling something. Puzzle elements involving pulling things may have been planned for.
Spr lamppost.gif
Checkpoint A checkpoint which looks very different compared to the final, but acts the same as the Sonic the Hedgehog checkpoints. You can place this with debug mode in Emerald Hill Zone, Hill Top Zone, and Metropolis Zone.
Sonic2pre hpzbg.png
Early HPZ background remains Used in an early version of the Hidden Palace background seen in a mock-up screenshot, but not in any real prototype. This was also in the Nick Arcade build.
Spr ball.gif
Ball According to concept art, this ball would bounce around and crush Sonic.
Spr fish.png
Piranha Badnik A piranha-type badnik which attacks Sonic in an arc-like motion. It is placeable with debug in the Nick Arcade build, but its graphics were garbled without using a PAR code.
Spr crocobot.gif
Gator A crocodile-type badnik. This badnik would have appeared in Dust Hill Zone according to a mock-up screenshot and would slowly move back and forth, opening its jaws when it got close to Sonic.
Spr trycerobot.png
Stego A triceratops-type badnik. This badnik would have appeared in Hidden Palace Zone according to a mock-up screenshot and would slowly move back and forth, and when Sonic approaches it it would activate its thrusters and move faster much like the snail badnik. In a later prototype, it was redrawn to use Sonic's palette.
Spr bouncer.gif
Crawl A prototype version of the Crawl badnik from Casino Night Zone. It still exists in the final.
Spr octopus.gif
Octus A prototype version of the Octus badnik from Oil Ocean Zone. This is not your usual Octus, as this one will fire a glowing bullet then quickly fly away horizontally if Sonic approaches it.
Spr seahorse2.png
Aquis A prototype version of the Aquis badnik from Oil Ocean Zone. Unlike its counterpart from the final version, this badnik behaves more erratically.
Spr 3eyefish.png
Bubbler's Mother A three-eyed fish-like badnik. According to concept art, this badnik would swim around in Chemical Plant Zone and drop Bubblers onto the ground around Sonic.
Spr bubble.gif
Bubbler A bubble-like badnik. According to concept art, this would have been dropped by Bubbler's Mother and would bubble up and burst when Sonic got near it. The palette is incorrect; it should be purple.
Spr cpzboss.gif
CPZ Boss Animation An unused sprite for the Chemical Plant Zone boss, presumably for when it was defeated.
S2-CPZ Unused object.png
CPZ Decorative Objects Unused decorative sprites from Chemical Plant Zone. These are present in the 2013 rerelease and can be placed in debug mode.
S2-HPZ Unused platform.png
HPZ Unused Platform A set of tiles in offset 075DD6 indicate that they were intended for a platform, but it isn't possible to know precisely how this is disassembled. A similar version is seen in 2013 rerelease and is used as an aquatic platform.

Unused Auto Demo

An auto demo for Metropolis Zone Act 3 was created, but it doesn't run during the title sequence. This demo is present until Beta 6 and removed from the final versions. This is possible to watch using this patch code FFFFF2:0004. The auto demo is partially incompatible with the level design.

Super Sonic

Sonic2 SWP Super Sonic.png

Super Sonic is partially implemented in this prototype, and can be accessed either via the Pro Action Replay code FFF65F:FF00 or by breaking open a monitor with the subtype 09 (unused in this prototype, and used in the final in two-player mode to grant a random item). The only aspect which is implemented is the rotating palette; Super Sonic's unique sprites, invincibility and ring drain are not present.

(Source: Sonic Retro (General Information))