Sonic the Hedgehog (prototype)

Sonic the Hedgehog
The title screen of the prototype of Sonic the Hedgehog.
Development staff
Publisher(s)	Sega
Video game overview
Platform(s)	Sega Mega Drive

This prototype of Sonic the Hedgehog (16-bit) is the only known early build of the final game. Though unknown how the game was found, it was leaked on The Hidden Palace around New Years Eve 2020.

Overview

The game includes following Zones: Green Hill Zone, Marble Zone, Sparkling Zone (Act 1) and Star Light Zone (Act 1). Upon reaching the end, the game resets back to the title screen.

General differences

Title screen

The intro plays exactly from the final game, but there are a few key differences:

• The big "SEGA", along with the sound effect, is absent in this build and remains just small generic text.
• "Sonic Team Presents" is absent in this build.
• The "PRESS START BUTTON" text, which goes unused in the final game, is present in this prototype.

Gameplay

HUD elements

Prototype	Final	Differences
		The "Rings" counter was originally just named "Ring". "Time Over" does not exist as when it reaches to ten minutes, it continuously loops back to the nine minute mark. During a "Game Over", the timer will still be counting in the prototype version.

Sonic

Sonic taking damage while invincible.

• Sonic's jumps in the prototype version are lower compared to its final counterpart, with a six pixel difference due to the "ObjectFall" change for the game's files.
• Sonic's deceleration speed is slower in the prototype build, due to it being $40 compared to final game's $80.
• Walking or jumping onto objects causes Sonic to lose some of his speed.
• When taking damage, Sonic will have no collision with the ceilings in the game.
• Sonic will not automatically run off screen when touching a Goal Plate or destroying a Capsule. Jumping shows Sonic's victory animation, which goes unused in the final game. It would eventually be repurposed for Sonic Mania as part of his victory animation.
• Every time the player collects fifty Rings, an extra life is granted to Sonic. This was later changed to one hundred in the final game, as it's very easy to grind that many Rings in a short period of time.

Objects

• The Star Posts and bonus points are absent in the prototype build
• When Sonic is invincible, spikes can still damage him.

Zones

Green Hill Zone

This is the most completed Zone in the game, with this being the only level with a functioning boss fight.

Image		Act	Description
Prototype	Final
		All	The sunflowers in the prototype version have a magenta disc floret instead of the green one for the final game. This color scheme is still seen at the end in the final game which suggests that it could've been changed late during the game's development.
			The rolling boulder is present in this build and does have some functionality to it. Although its sprite can be found in the final game via debug mode, it cannot be placed. This boulder can be pushed around, but it is quite buggy in this build as Sonic can go through the ground, It also has no gravity if the player were to stand on it, which could explain why it was removed from the final game.
		1	Upon starting the level, a Moto Bug will spawn very close to the stage before even getting to the first three rings. This was removed in the final game.
			The palm tree next to the first bridge of the level did not have a spring in the prototype version.
			The design of these level chunks was changed due to one of the foreground cliffs being jutted out.
			These spikes on the wall were removed in the final game.
			The spring surrounded by spikes had another set on each side. This was shortened to half that in the final game.
			Above the two S tunnels, the platforms are absent in the prototype build. However, there is an invincibility monitor upon reaching it.
		2	The rock above the spikes was removed in the final game, with the other one adding a yellow spring on top of it. The line of rings was also moved upwards.
			Behind the Speed Shoes Monitor, a 1-Up Monitor was replaced with a Shield Monitor.
			In the prototype version, a row of eight rings were placed underneath another row.
		3	At the beginning of the stage, a Shield Monitor was replaced with an Invincibility Monitor, the rock was replaced with the spring, and the Buzz Bomber here was removed in the final game.
			At the first set of spikes, a checkered ball was placed there (possibly to troll the player), and both a singular spike (below Sonic) and crumbing platform (above Sonic) were added.
			A set of spikes were removed and a green Newtron was added on the wall to the right in the final game.

Marble Zone

This is the last zone to have a complete set of three Acts.

Image		Act	Description
Prototype	Final
		All	The Spikes Badnik is not present in this zone and it also uses a different color pallet. These were replaced with Caterkillers in the final game.
			Above the player in the sky are several UFO sprites, which were seen in pre-release images, along with in the movie Wayne's World. They were later repurposed in the 2013 remake and can be placed via debug mode.
		1	A platform above this set of Rings is not present in the prototype build.
			There are Rings missing between these glass crushers.
			Only one Batbrain exists when reaching the first pushing block.
			The block is much further from the switch when compared to the final game.
			The horizontal spike crusher that can be found in the files for the final game is seen here and can be placed within debug mode. It was replaced with a vertical one.
			A set of spikes placed next to this Shield Monitor was replaced with a Star Post in the final game.
		2	A Ring Monitor was placed at the top of the column in the prototype version of the game. It was removed possibly as there was no way to reach it in normal gameplay.
			In the prototype version of the game, the player would've originally had to jump repeatedly on top of this glass crusher in order to continue through the game. This was changed in the final game where all the player needs to do is jump onto a switch right next to it.
			At the tunnel that ends with a red spring trap, the prototype has three Spikes Badniks with the final version replacing it with two Caterkillers.
		3	There is one Ring on each of these three pillars in the prototype version, perhaps some sort of decoration was planned.
			The secret door under the incline originally had three Ring Monitors. This was replaced with a Caterkiller in the final game.
			At a dead end of these glass crushers, a 1-Up Monitor was originally granted in the prototype version. This was replaced with a Shield Monitor in the final game.
			The layout of these fireball launchers were changed between the prototype and final builds of the game.
			While Act 3 does not have a boss in this build, a Goal Plate is present at the end of the Act.

Sparkling Zone

The original name before it was changed to "Spring Yard Zone", only Act 1 in this zone is fully playable in this build, with both Act 2 and 3 being almost empty: Act 2 has some object placements at the beginning and Act 3 only has a Static Monitor at the beginning of the level.

Image		Act	Description
Prototype	Final
		All	The Spikes Badnik has a another different color pallet in this build, which was replaced in the final game.
			The background in the prototype build was originally a starry night sky with colorful neon lights and buildings, even signs that say "Go Go", "Good Luck", and "Goodbye" replicating a more Casino-like feeling. In the final game, the buildings remain distant with mountains, clouds and a grassy field replacing this.
		1	Upon reaching the "COPE" sign, the bumper was originally surrounded with spikes on it. This was removed possibly due to fairness.
			In the halfpipe section, immediately below the bumper area above, a block with both a red and yellow spring attached to it are not present in the prototype version of the game.
			This top bumper, slightly above solid ground connecting to the bumper area and the first "elevator" section, is not absent in the prototype version of the game.
			At the left end of the level's top path, the second Ring Monitor was removed in the prototype version of the game. The four spike balls were also cut down to two in the final game as there would be no way for the player to easily continue.
			Around the middle of the top path's middle section for the level, with the building in the prototype version being moved over to the right, a moving platform was placed next to the triangular slope on the left which was removed from the final game. A slope was also added with the spring being changed to being vertical instead of horizontal.
			This slope in the prototype version was replaced with a platform and spring in the final game.
		2	At the beginning of the level, there was originally a slope placed in the prototype version of the game. This was changed to a flat plain in the final game.
			This slope was changed to a shallower incline for the final game.

Labyrinth Zone

This Zone is unplayable and has no water throughout the entire zone. If Rings are placed in debug mode, their color pallet will appear entirely black. Crystals in this level also have a smaller design compared to their final counterparts.

Image		Act	Description
Prototype	Final
		All	The background in the prototype version was originally a giant cave with beams of light coming out from the top. In Act 2, its position axis was shifted showing only half the artwork with Act 3 having it gone completely. In the final game, it was changed with a bunch of stone bricks.
			There are brick wall tiles which are not found in the final game, but do appear in the 8-bit versions of the game. These are placed in some areas of the stage where air bubbles were placed in the final game. This suggests that air pockets were once planned before it was changed.
			Pillar decorations did not exist in the prototype version of the game.
		1	Upon loading into the level, there is a graphical error when walking down the initial path where the player can jump onto a block above and jumping will do a vertical zip. Doing this will allow Sonic to walk in the air and can even outrun the camera before catching back up to him. This was fixed in the final game by placing another block on top of it and disabling vertical looping for this Act.

Star Light Zone

A very early version of this Zone, with many level layouts being unfinished. The stage itself has a more "under construction" type of feeling compared to the final game. Although the zone are roughly similar to their final counterparts, the level design itself is completely different. Many include numerous small platforms clustered together, fewer loop-de-loops and winding paths, and more opportunities to fall into bottomless pits. Although there are no enemies in the prototype's levels, the fireball launchers do exist.

Image		Act	Description
Prototype	Final
		1	In thus prototype version, this area of the level only contains falling platforms. In the final game, this was replaced to become a secret area behind a breakable wall where three ring monitors would appear.
			The ledge where it would contain a 1-Up Monitor in the final game was originally a bottomless pit, with a expanding platform below.
			The prototype version of the game has the Goal Plate misplaced being halfway in the ground. This was later fixed in the final game.
		2	Near the end of the stage of the prototype version, there are some corrupted sprites where only the top left corner of it can be stood on. Upon standing on it, it will travel downwards a slight distance, which are similar to fully-implemented elevator platforms in the final game for this same level.

Clock Work Zone

The original name before it was changed to "Scrap Brain Zone" with the most uncompleted work out of the rest.

• The name of the zone is displayed as "Clock ork Zone", as the "W" is missing due to a lack of title cards sprites. Even so, there is still some space for the letter.
• The background of the zone uses the level chunk artwork.
• The Debug menu only includes Rings, Static Monitors and Crabmeats.
• Pits that the player can fall into do not work where it can either zip Sonic to the top of the level or allowing him to stand below the level.
• Conveyor belts and warp tubes to exists in the game, but have no functionality in them.
• The rotating discs do appear in the Act 2 and are somewhat usable. There are also smaller versions of them present that do not exist within the final game.
• Act 3 does not exist in this version. Even if the player were to hack the game, it would load an empty level with a blue background.

Special Stage

Special Stage.

Only one Special Stage exists in the game's files with its layout being very simple, implying that this design of the stage was only temporary for testing purposes.

• Only is used for jumping, while and are, respectively, used to speed up and slow down the stage's rotation. The START button, which would usually pause the game, will reset the rotation speed of the level.
• Aside a few cluster of rings around the level, only two bumpers exist in this stage.
• The blue ones (with "GOAL" on them) have no animation nor functionality, but their second frame (red tiles) will spin the stage around rapidly like in the final game would before pausing for a moment to then resetting the stage all over again.
• Instead of a Chaos Emerald, a green block is used as a placeholder. Touching it does nothing, however.
• Goal tiles are split into two separate objects.
  • The blue ones (with "GOAL" on them) have no animation nor functionality, but their second frame (red tiles) will spin the stage around rapidly like in the final game would before pausing for a moment to then resetting the stage all over again.
• Debug mode is deactivated in this stage meaning the player cannot move freely or place objects of any kind.
• The UP and DOWN tiles do not animate and seem to function like the Reverse blocks instead of adjusting the stage's rotation speed.
• Collision detection seems to be less refined as Sonic is able to stick onto tiles much easier than in the final game.

The player can go Out of Bounds if one were to remove some objects in the level editor. Falling will show garbage data with colored blocks, bumpers, and Goal spheres being present in the area. It is also possible that doing this can crash the game.

• Attempting to go further down into the garbage data will cause the graphics to deform and will have the collision to become more glitchy to the point where Sonic can't go anymore downwards.
• Going left or right will also cause the graphics to deform, but the player can continue going left or right until the strip of garbage data loops.

Early demo cycles

If the player lets the game sit for a while, a demo cycle plays where it would show Sonic going through a small portion of the zone before fading out to the title screen again. However, upon starting the gameplay, Sonic immediately dies from a Badnik less than five seconds in. This is possibly due to the changes between this version and another earlier one of the game.

Although the demo gameplays show Green Hill Zone, Marble Zone, and Sparkling Zone of Act 1, a demo of Star Light Zone (where he falls off stage) and the Special Stage also exist within the game's data.

Unused content

Unused sprites

Image	Name	Description
	Smoke	Some sort of smoke. These also go unused in the final game where the files for it can be found for it being the Star Post graphics.
	Water splashes	Some earlier water splashes meant for the Labyrinth Zone, which are not used in this prototype as there is no water implemented to the game yet and were later changed in the final game. However, these do get used in Sonic the Hedgehog CD.
	Sparkles	A couple of sparkle sprites meant for Invincible.
	Fireballs	A small fireball similar to what the Fire-Breathing Statues shoot in Labyrinth Zone.
	Ballhog moveset	A complete programmed and moveset of the Ball Hog Badnik seen in Scrap Brain Zone. This version of the badnik is completely different compared to the final game where it would walk from side to side and drop bombs down vertically at the player. When the ball is dropped, it will explode either on the player or on the ground. The explosion for it can also be found in the files for the final game where it would also have been used for the Buzz Bomber missile explosions planned for the game.
	Spring	A spring found in the boss attachments art file. This was possibly intended for the Sparkling/Spring Yard Zone boss battle before being changed in the final game.
	R block	A different R block variant meant for the Special Stage where it would've functioned to reverse the level. However, there is no code attached to this object.
	Skull icon	A skull icon meant for the Special Stage. Although its purpose is unknown, it's possibly that it had something to do with either death or losing.
	Magnet icon	Appears to be a magnet icon that was meant to be use for Special Stage. While it's unknown what the purpose of could be, it is suggested that it could either be used as an item to allow Sonic to pull any rings towards him whenever he nearly reaches them or an object to either pull Sonic in or push away.
	Chaos Emerald	The graphics for the blue Chaos Emerald are present in the game's files, despite it being absent from the Special Stage. The presence of only the blue Chaos Emerald without all the others may imply that the Emeralds were planned to all be blue at this point in development, similar to the 8-bit version of the game.
	UFO	A sixth frame for the animated UFOs in Marble Zone.
	Unknown objects (02 and 03)	Two objects that appear in a glitched state when hacked into the game, both objects existing during the game's earliest stages of development and can even be found in a recording of the game's work. Though it is unknown what these objects would be, Object 02 will load some sort of pulsating object with Object 03 having a rectangular shape. Both of them have fixed coordinates and cannot be placed anywhere in a level. However, if the player were to hack the game's files to load in Object 03, six blocks will then be displayed on the screen by default, with the seventh block remaining hidden above the player's view.
	Unknown object (04)	The object is similar to Object 03. The only differences is that it is animated and can be placed anywhere in the X axis having the Y axis fixed.
N/A	Unknown object (05)	This object is invisible when loaded into the game.
	Unknown object (06)	Spawns a red dot on the screen and allows the object to follow the HUD.
	Animation test	This object seems to that it was used to test all of Sonic's animations. Whenever the player jumps, it will move onto the next animation/sprite upon landing.
	Unknown object (1B)	A static object with no collision detection on it. In the final game, another object with the same ID number generates the water surface in Labyrinth Zone.
	Switch	An object that acts like any other switch to open a closed passage. If hacked into the game, it will load some glitched sprites. It's possible that this would've been used in Marble Zone as it's the only Zone in this build that features switch-based interactions of any kind. This object can also be found in the final version and still remains unused. This object might've only been used for testing purposes.
	Switch door	A door that opens by pressing a switch. Its ID file is used in the final version for a one-way door object in Scrap Brain Zone.
	Jaws Badnik	Meant for the Labyrinth Zone, but go unused in this prototype due to the level being incomplete. When loaded, its color palette will load Sonic's and can only swim left.
	Burrobot Badnik	Meant for the Labyrinth Zone, but go unused in this prototype due to the level being incomplete. When loaded, it will have a different color palette using purple and yellow. Its function will behave like the Burrobots in the final game.
	Roller Badnik	Can be placed in Sparkling Zone in game via debug mode. Its behavior is different compared to the final game. Its color palette in the prototype is purple and yellow with the final game being blue and red. The Badnik cannot be defeated. When spawning the Badnik into the game, it stands stationary until the player approaches it and takes off after they pass by it. In the final game, it enters on screen by rolling into the player's view. It does no uncurl no matter how close it is to the player.
	Splats	Can also be found unused in the final game, only difference is the color palette.
	Seesaw	Can be placed in Debug mode. The object itself is complete in this build, but it does lack the iron ball for it to be used.

Unused sound effects

Many of these unused sounds were eventually replaced in the final game.

Clip	Filename	Description	Replaced by
	$A1	Sounds similar when touching a Goal block in the Special Stage.	Checkpoints sound effect
	$A9	A longer, higher-pitched version of the rolling sound.	The sound used for touching the speed/Reverse blocks in the Special Stage
	$AD	A duplicate sound effect of destroying a Badnik destroyed, but lacks noise PSG. However, it does get reused in future Sonic games (such as Sonic CD, Sonic the Hedgehog 3 and Knuckles' Chaotix)	Air bubble sound effect
	$B0	A low-pitched siren sound.	Buzzsaw sound effect from Scrap Brain Zone
	$B1	A faster, higher-pitched siren, possibly ripped straight out of Pac-Man.	Electricity sound effect used for Scrap Brain Zone
	$B2	Possibly sounds like a buzzer. This sound effect can also be found in the files for Micheal Jackson's Moonwalker.	Drowning sound effect
	$B3	A rough, low-pitched sound that quickly rises and falls in pitch. Possibly something destroyed?	Falling fireballs sound effect from the Marble Zone boss fight
	$BA	Possibly an early version of the sound used by the color-changing blocks in the Special Stage. It does resemble the sound used by the color-changing bars in Casino Night Zone from Sonic the Hedgehog 2.	Color-changing blocks sound effect
	$BF	Two quick, harsh-sounding noises that loop indefinitely.	Continue sound effect.
	$C2	An alternate sound effect of destroying a Badnik destroyed, with this one sounding a bit harsher compared to its final counterpart.	Underwater timer sound effect.
	$C3	A deeper version of the bomb explosion sound possibly meant for for the Bullhog Badniks.	Giant ring sound effect
	$C9	A harsh, vibrating noise.	End-of-stage point marker sound effect
	$CA	Possibly footsteps walking away.	Special Stage warp sound effect
	$D1	A louder version of the waterfall found in Green Hill Zone. This sound effect can also be found in the files for Micheal Jackson's Moonwalker.	Deleted in the final game
	$D2	A strange rhythmic pounding sound. This sound effect can also be found in the files for Micheal Jackson's Moonwalker.	Deleted in the final game

Unused music

Aside some of the changes in the music themselves, these tracks go unused as the were not implemented into the game yet.

Clip		Name/Level	Notes
Prototype	Final
		Final Zone
		All clear
		Staff Roll	The game immediately switches to the title screen after beating Star Light Zone Act 1.
		Continue	There are no continues in this game even after getting a Game Over.
N/A		Drowning	Due to the pointers being invalid, the game crashes if the player were to try to listen to it.
N/A		Got Chaos Emerald	The filename ($93) is in the game's files, but it is completely missing as the sound ID does nothing.

External links

• Sonic the Hedgehog (Prototype) on The Cutting Room Floor
• Sonic the Hedgehog (Prototype) on Hidden Palace

Sonic the Hedgehog (16-bit)

---

Main article (Blue Sphere) · Staff · Manuals · Glitches · Beta elements · Gallery · Pre-releases (prototype) · Re-releases (2001, 2005, mobile, GBA, iPod, 2013, 3D, Sega Ages)

*Appears in re-releases of the game only
V·T·E · {{Sonic 1 (8-bit) info}} · Category