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Sonic the Hedgehog (16-bit) (prototype)/Hidden content

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This list is incomplete.
The following list has been marked as incomplete. If you can, please complete it.

TODO:

  • Unused level chunks
  • Unused debug/edit mode features from earlier builds
  • Unused/early GHZ layout data
  • Perhaps stuff that would go unused in the final too, for completion's sake

Level select

Sonic1Proto MD LevelSelect.png

Enabled by default. Simply press A+Start on the title screen.

Edit mode

Sonic1Proto MD DebugMode.png

Enabled by default. Highlight a Zone in the level select and press and hold A.

Unused content

Art

Art Description
Sonic1Proto MD Sprite UnusedFont.png
An 8x8 font that comes in three different shades of grey, located at $18000.
Sonic1Proto MD Sprite Smoke.png
Smoke effects, located at $2656E.[1] Their VRAM spot would be overwritten by the Lamppost in the final.[2]
Sonic1Proto MD Sprite WaterSplash.png
Water splash effects for Labyrinth Zone that go unused due to a lack of water, located at $26672. In this prototype, the splash has simpler shading and uses Sonic's palette.
Sonic1Proto MD Sprite Sparkle.png
Sparkle effects, located at $267D4.
Sonic1Proto MD Sprite UnusedFlame.png
Small flame effects, located at $26BF6.[1]
Sonic1Proto MD Sprite EnemyPoints.png
Combo bonuses awarded from enemies and breakable objects, located at $2E6C8.[3] All numbers are loaded in VRAM in preparation for combos, but defeating enemies consecutively only awards 100 points in this build.
Sonic1Proto MD Sprite BossPieces.png

Sonic1Proto MD Sprite BossSpring.png
An assortment of parts for the Egg Mobile, located at $60864. While most of the parts here eventually see use for the bosses in the final game, there is a spring attachment that never saw use.[1] The second image is an attempt at assembling the spring attachment.
Sonic1Proto MD Sprite SpecialStage SkullBlock.png
Skull block for the Special Stage, located at $6512E.[4]
Sonic1Proto MD Sprite SpecialStage UBlock.png
"U"/magnet block for the Special Stage, located at $651FE.[5]
A Chaos Emerald for the Special Stage, located at $65B76.[6]
Sonic1Proto MD Sprite UnusedUFOFrame.png
An unused animation frame for the UFOs in Marble Zone, located at $6C8A0. Use PAR code 011430:0006 to restore it in the animation script.[7]

Objects

Placeable in edit mode

Art Description
Sonic1 MD Sprite Monitors.png
Static monitor that does nothing when broken.
Sonic1Proto MD Sprite Splats.png
The infamous Splats enemy, placeable in Marble Zone. This Badnik is fully coded in this build, and when placed it continually bounces forward, only changing direction when it hits a wall. While it uses Sonic's palette line in the object list, it uses the second palette line when placed. Its object ID is 4F.
Sonic1Proto MD Sprite PurpleRoller.png
Roller enemies for Spring Yard Zone. They are fully functional, and use the second palette line, making them look purple and yellow.
Sonic1Proto MD Sprite SLZSeesaw.png
Seesaws for Star Light Zone. While fully functional, they don't have the spike ball that helps propel Sonic into the air. Its object ID is 5E.

Others

Art Description
Two graphicless objects that date back to the earliest stages of the game's development in February 1990.[8] Object ID 02 is a "pulsating" object, and 03 is a tall rectangular object. Both objects cannot be placed anywhere in a level as they have set coordinates, and cannot be interacted with by the player.
An animated object similar to ID 03, which can be placed anywhere on the X axis but has a fixed Y axis. Its object ID is 04.
An invisible object. Its object ID is 05.
An object that follows the HUD. Its object ID is 06.
A static, collisionless object with two variations, but no corresponding graphics. Its object ID is 1B. In the final game, this object was replaced with the water surface object for Labyrinth Zone.
An unused switch that acts like any other switch that opens a closed passage. Its object ID is 1D. It remains unused in the final game.
Sonic1Proto MD Sprite EarlyBallHog.png

Sonic1Proto MD Sprite BallHogBomb.png
Ball Hog, based on its original front-facing design seen in prerelease material, going unreferenced in the object table. They move from side to side, periodically stopping to drop bombs directly downward. The main Badnik's object ID is 1E, while the bomb's ID is 20.
A door object, operated by pressing a switch. It also has a variant that is set up to use other tiles, has no collision, and doesn't react to switches. Its object ID is 2A. In the final game, this object was replaced with the one-way doors for Scrap Brain Zone.
Jaws-spr.png
Jaws enemies for Labyrinth Zone, which exist in the object table but go unreferenced. They are fully functional. Its object ID is 2C.
Burrobot-spr.png
Burrobot enemies for Labyrinth Zone, which exist in the object table but go unreferenced. They use the second palette line and do not start buried underground, but are otherwise functional. Its object ID is 2D.
Sonic1 MD Sprite GiantRing.gif
The Giant Ring that would transport Sonic to the Special Stage. Its coding is different in that once Sonic touches it, instead of disappearing instantly, he sparkles for a couple of seconds and then "warps" away. The coding is incomplete beyond this point, so Sonic reappears a couple of seconds later. This "warping" code remains unused in the final game. The Giant Ring's object ID is 4B, while the warping effect has an object ID of 4A.

Audio

Music

Audio Description
Ending theme; sound ID 8B.
Final Zone; sound ID 8D.
Continue screen; sound ID 90. Goes unused in this build as Continues are not implemented yet.
Staff roll medley; sound ID 91.

Sound effects

Many of the sound effects listed here are unique to this prototype and would be replaced by other sounds in the final.

Audio Description
Sound ID A1. Similar to the sound played when exiting a Special Stage. Replaced by the checkpoint sound in the final.
Sound ID A5. Used by the unused Ball Hog's bombs when they explode. Remains unused in the final.
Sound ID A8. This sound effect is used by the unused warping effect in this build. Replaced by the aforementioned Special Stage exit sound in the final.
Sound ID A9. A longer, higher-pitched rolling sound. Replaced by the sound for the speed/Reverse blocks in the Special Stage in the final.
Sound ID AA. The splashing sound for entering water; unused as there is no water yet.
Sound ID AD. A duplicate of the Badnik/monitor explosion sound. Replaced by the sound for breathing in an air bubble.
Sound ID B0. A low-pitched siren sound that loops endlessly. Replaced by the buzzsaw sound effect.
Sound ID B1. A higher-pitched Pac-Man-esque siren that also loops. Replaced by the sound for Scrap Brain Zone's electrical hazards.
Sound ID B2. Some sort of buzzer sound. Replaced by the sound played when Sonic drowns.
Sound ID B3. A rough sound effect that quickly rises and falls in pitch. Replaced by the sound for Scrap Brain Zone's flamethrowers.
Sound ID B8. Similar to the spike sound. Remains unused in the final.
Sound ID BA. Sounds similar to the sound used by the drop targets in Sonic 2's Casino Night Zone. Replaced by the sound for hitting the diamonds in the Special Stage.
Sound ID BB. The sound used for the Labyrinth Zone doors and Scrap Brain Zone trapfloors; unused as those objects don't exist yet.
Sound ID BC. The sound used for the transport tubes in Scrap Brain Zone; unused as they don't function yet.
Sound ID BF. Two quick, harsh-sounding notes that loop indefinitely. Replaced by the Continue sound.
Sound ID C2. An alternate version of the Badnik/monitor destroying sound. Replaced by the underwater warning bell.
Sound ID C3. A deeper version of the bomb explosion sound heard in the next sound ID slot. Replaced by the sound for entering a Giant Ring.
Sound ID C9. A harsh, vibrating sound effect. Replaced by the sound for finding a hidden point bonus at the end of an Act.
Sound ID CA. Sounds like footsteps walking away. Replaced by the sound played when warping to the Special Stage.
Sound ID D1. A louder version of the Green Hill Zone waterfall sounds. Cannot be played in the sound test, and completely removed in the final.
Sound ID D2. A strange rhythmic pounding sound that loops endlessly. Cannot be played in the sound test, and completely removed in the final.
Sound ID D3. A fiery noise that progressively oscillates, looping endlessly. Cannot be played in the sound test, and completely removed in the final.

Green Hill Zone alternate palette

Sonic1Proto MD GHZ NightPalette.png
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

There is an alternate palette intended for Green Hill Zone that exists in the ROM, but is not normally used. By changing ROM address 0x1AF6 to 1D 9C and 0x1AFE to 1D BC, or by using Game Genie codes XTPA-B4H0 and 1TPA-B4H8, this palette can be accessed. This palette is almost identical to the one used for the high score screen in the Mega Play version[9].

Sparkling Zone early object layout

Sonic1Proto MD SZ EarlyLayout Badniks.png
Sonic1Proto MD SZ EarlyLayout RedButton.png

An unreferenced object position list that seems to have been for an earlier layout of Sparkling Zone Act 1 can be found at ROM address 0x729CA. To access it, change ROM address 0x70040 to 29 CA.[10]

When loaded in-game, this layout has numerous differences, such as a large abundance of Badniks including Moto Bugs, and a button that flashes red (which would go unused in the final game). Interestingly, some of the object positions seem to match up with prerelease screenshots from earlier builds.

References

  1. 1.0 1.1 1.2 [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974737 by Rika Chou
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974737 by Rika Chou
    ]
  2. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974802 by vladikcomper
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974802 by vladikcomper
    ]
  3. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #976355 by Nemesis
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #976355 by Nemesis
    ]
  4. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974732 by Rika Chou
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974732 by Rika Chou
    ]
  5. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974730 by Rika Chou
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #974730 by Rika Chou
    ]
  6. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #976356 by Nemesis
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #976356 by Nemesis
    ]
  7. https://tcrf.net/Proto:Sonic_the_Hedgehog_(Genesis)#Unused_Sprites
  8. [
    YouTube
    Sonic initial development site.Sega R&D news footage of Feb 1990.
    YouTube
    Sonic initial development site.Sega R&D news footage of Feb 1990.
    ]
  9. [
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #980382 by MrLordSith
    Sonic Retro
    Sonic Retro forum thread: Sonic the Hedgehog (Prototype); post #980382 by MrLordSith
    ]
  10. https://tcrf.net/Proto:Sonic_the_Hedgehog_(Genesis)#Unused_Object_Positions


Sonic the Hedgehog (16-bit) (prototype), prerelease version of Sonic the Hedgehog (16-bit)
Sonic1Proto MD Title.png

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