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Proto:Sonic the Hedgehog CD (Sega CD)/v0.02

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This is a sub-page of Proto:Sonic the Hedgehog CD (Sega CD).

To do:
Layout differences in Palmtree Panic/Salad Plain, plus any potential unused sprites in the proto.

v0.02 is the earliest known prototype of Sonic CD for the Sega CD. The build is dated December 4th, 1992 (two days and nine months before final), predating the previously discovered 510 prototype, and was created so the game could be shown at the Japanese Yuusei Sega World event that year. It was dumped by drx on October 26th, 2019 as part of Sonic Month.

Many things haven't been implemented, or are in a buggy state. Gameplay wise, only Palmtree Panic Acts 1 and 2 are present on the disc, (although R3-2 and R5-1 do have leftover stage data). This is also the only known prototype that acknowledges the infamous "R2", which is present (but not selectable or functional) in the Time Attack screen.

The game is always referred to as CD Sonic the Hedgehog, which is odd as the Japanese spelling does place the CD after the Sonic the Hedgehog part. An extra SEGA screen is present at the start, complete with the classic "Sey-Gah!" chant. It was removed after the 512 prototype.

Title Screen

v0.02 - v0.28A Final (US)
Soniccd510titlescreen.png SonicCDtitle.png

The title screen is different from how it would be in v0.51 onward:

  • The game's title is CD Sonic the Hedgehog, rather than Sonic the Hedgehog CD.
  • A gold emblem with the Sega logo and the copyright date (1993) is present, but was removed from the final version.
  • The prototype's title screen is 320×224 at 60fps, but was later changed to 256×224 at 20fps.
    • All of the perspective effects in Sonic CD are calculated by a co-processor on the Sega CD, which produces tiles that have to be transferred to Genesis VRAM to be displayed. Given that this process has some bandwidth limitations, and that the Special Stage runs at the same resolution and framerate, it is likely that this accounts for the resolution drop in the final title screen.
  • The clouds are scrolling from left to right, instead of using the sprite scaling layer.
  • Little Planet is more washed out with some dithering.
  • A text string is present at the corner right, crediting Japanese singer Keiko Utoku of the then-major J-Pop idol group Mi-Ke for "Sonic - You Can Do Anything", for press purposes. The song itself also plays here, instead of the opening cutscene.

Salad Plain (Palmtree Panic)

Palmtree Panic was originally called Salad Plain, according to the Time Attack screen (see next section below).

Past Present Bad Future
CDSONIC0.02-SP1B.png CDSONIC0.02-SP1A.png CDSONIC0.02-SP2D.png
  • The color palette for this stage is different, featuring some slight differences. the palette data and palette cycling data are still in the final game.
  • It's not possible to get a Good Future in this build. However, the level files for Good Future are present on the disc.
  • To access the Good Future variants of the levels, change bytes at 0xA1A in the Track 1 binary to 0070 for Zone 1, and 0058 for Zone 2.
  • The Good Future variants use the music for the Past variants, despite the track for Palmtree Panic's Good Future being present on the disc.
  • The present has a different background, the most notable difference being the shorter and less geometric mountains. This early background is the basis for the other time zones' backgrounds, which were kept unchanged in the final game.
  • The palm trees have a more asymmetrical design.
  • Amy is nowhere to be found in the present version of Palmtree Panic Zone 1.
  • The big loop at the beginning of the present version of Palmtree Panic Zone 1 is missing. In its place is a small ramp and a spring.
  • Breakable parts of the walls have not been added to the levels yet.
  • The yellow spring that bounces Sonic away from the goal is missing.


You don't make friends with salad, Sega figured.
  • The graphics are extremely basic.
  • Only Palmtree Panic 1/2 are normally selectable, and is referred to as "Salad Plain." Although by hex editing values on the Time Attack menu, it is possible to bypass the restrictions of being stuck with R1-1 and R1-2 and you can select other levels, although there are no other Zone previews on the left when going beyond Salad Plain. Most levels unfortunately lead to a black screen (including R2) however R3-2 and R5-1 still have existent level data leftover in the prototype and you will be taken to a broken Palmtree Panic Zone level upon selecting either one. R7-3 strangely, takes you to a unused level select that's seen in later prototypes instead of black screening. The unused level select it's self is barebones and selecting anything but the first option will take you back to the Time Attack menu.
  • This is the only prototype that explicitly references the scrapped "R2" as a level entry in the Time Attack menu, without having to hack the game to enter the level select. All other known versions of the game skip from R1 (Palmtree Panic) directly to R3 (Collision Chaos). It is unknown why R2 was cut, although Jim Trethewey (who helped develop the Windows port) said in an interview that Junetsu Kakuta (who worked on the game) implied that the level was removed due to quality and design concerns.
  • Collision Chaos' present theme is used here instead of the actual Time-Attack music.


  • Some of Sonic's frames are bugged. His "Peel-Out" animation isn't implemented.
v0.02 510 - Final
Note: The last sprite in the animation has part of it cut-off in-game. SCDImOuttaHereFinal.gif
  • The sprites for the "I'm outta here!" easter egg are extremely different.
Sonic 1 v0.02 510 - Final
Sonic1 Spring.png SonicCD 0.02 Spring.png SonicCD Spring Final.gif
  • Sonic still uses his spring frame from the original Sonic the Hedgehog, but it's not exactly the same - his shoes have been redrawn and updated to add the white stripe. The spinning animation however does exist in this prototype, and is used during the time travel sequence.
  • The lives counter is placed slightly higher than normal, and there are no zeros in the SCORE and RINGS counters. Oddly enough, the RINGS counter does not flash red when the player has 0 rings.
  • Active time warps are not yet indicated on the HUD.
v0.02 510/v0.28a v0.52-Final
Soniccd 0.02 yousay.png
  • The goal-post reads "You Say!", which might be a pun on the word "Yuusei" (the name of the event where this build was featured) [1], and do not spin when the player passes them. This also appears in the earliest screenshots available of the game.
  • The graphics for Palmtree Panic are more uniform, with less distinctions among the timezones.
  • The time-attack mode looks nothing like the final, and features the early name for Palmtree Panic.
  • The time-travel graphic is extremely basic, featuring only blue lines on a white background.


v0.02 Final
v0.02 v0.70 - Final
  • Palmtree Panic's past theme is stored as CD audio, while in the final it was remade into sequenced PCM audio. It also uses a different mix.
v0.02 - v0.28A Final
  • The time warp sound is different, and very grating on the ears. This would be changed in v0.51, and again for v1.05.

Gameplay Differences

"I'm outta here!"


The famous "I'm outta here!" Easter egg doesn't work properly. The camera doesn't lock and Sonic dies when he hits the bottom of the level, instead of getting a Game Over. For some reason, the player, upon re-spawning, will be able to keep the rings they've collected before triggering.

Time Traveling


Time traveling doesn't seem to work correctly, as attempting to travel using the spinners will instead cause the current level to restart rather than letting Sonic warp through time (the time warp appears short here because the black screens were trimmed out of the GIF).

Physics Oddities


Sonic 1's programming was used as the basis for Sonic CD, but at this point in time the physics have yet been fully optimized for this game, resulting in many oddities listed below:

  • In the Bad Future, colliding with solid collision tiles whilst standing on the collapsing diamond platforms could cause several oddities, like the infamous slope glitch.
  • Charging a Peel-Out for about 21 seconds warps Sonic near the end of the act. Charging it several seconds longer will crash the game.
  • Running fast or charging a Spindash or Peel-Out does not cause the camera to move.
  • Sonic takes a lot longer to charge a Super Peel-Out. The maximum speed it gives is also limited by the Sonic 1 speed cap.


  • The game cannot be paused.
  • Two additional monitors are present in this build.
    • Blue Ring: When broken, Sonic will run faster and be granted temporary invincibility. In later builds it acts like a triple-layered shield (as-in, it gives three additional hits), but was later removed from levels.
    • Clock: Meant to freeze time for a few seconds, but is incomplete as it only freezes the animation of objects other than Sonic.
  • Pressing START on the second controller spawns a second Sonic. That player will then able to control that Sonic.
  • Collecting 50 rings does not spawn a Special Stage ring at the end of a level.
  • The player can not change the direction while roll-jumping, like in the main Genesis Sonic games.
  • If the player loses all their lives or beats Salad Plain Zone 2, a "COMIN' SOON" screen will appear, after which the game resets. This screen actually made it into the final game, and can be viewed using the level select.
    • The Palmtree Panic Good Future Theme plays on this screen, instead of the Invincibility theme used in later builds. This is in part due to the fact that that music track is not present yet.
  • The level-select is present in the files, and can be accessed through modding. Change bytes at 0xA1A in the Track 1 binary to 011A.
    • Only up to "COMMING" is accounted for. It is also instead marked as "COMMING SOON".
    • Oddly, selecting anything other than "1-1-A" will send the player to the Time-Attack menu.

Unused objects

To do:
Add documentation of the leftover glass bumper object of Collision Chaos seen here

Object 27

This appears to be an unfinished tilting platform object. Its graphics get loaded at certain points in the stage, usually around the small logs. It was scrapped by the 510 prototype.

Object 29

This is likely a preliminary swinging platform object for Tidal Tempest. Interestingly, if spawned with the subtype "00" in the game, it underflows and tries to spawn 255 sections of the "chain," causing immense load times and lag.

Object 04

This object does exist in later prototypes and in the final game. It seems it was meant to be an object that would overwrite tiles, likely trying to create a "flowing waterfall" effect. It seems it didn't get very far in development.

Object 08

This is by far the most interesting unused object in the prototype. It appears to change level layout when Sonic touches it. Nothing like this exists in later prototypes or in the final game.

(Source: Nat the Porcupine)

Unused sprites

To do:
Sonic has a ton of animations that aren't used here but are in the final, as well as some straight-up unused ones. Document them, and see if there are any other unused sprites.
Artwork Description
SonictH1 Gen Dead Sprite.png
A black-and-white death sprite, whose purpose is unknown. This is also present (and unused) in the original Sonic the Hedgehog, so it's probably just a leftover from that game.
SonicCD002-Unused Disc Statue.png
This is an object that exists in the debug list - however, placing it does nothing. The graphics for it do exist in the data, and it seems to be a bridge post of sorts, similar to those found in other Sonic games.

Collison Chaos Leftovers

Collison Chaos Act 2 or R3-2, has leftover data in the ROM if you manage to bypass the restrictions in the Time Attack menu and select R3-2. The level is a copy of Palmtree Panic Zone Act 2 Past, plays Present's music, and has the Present version's object layout. What's special about this level however is that on the wooden bridges seen in the video, there are objects that knock you back that are very reminiscent to Collison Chaos's glass bumpers seen in Act 2.

Possible Quartz Quadrant Leftovers

Quartz Quadrant Act 1 - or R5-1 - also appears to have some leftover data, should the player manage to bypass the restrictions in the Time Attack menu and select R5-1. This level is a copy of Palmtree Panic Zone Act 1 Past, but with Present's music and object layout. Other than that though, there is nothing especially peculiar about the level, and the level does not appear to have any objects left over from Quartz Quadrant.