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

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

Edit mode

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

Unused content

Art

Art	Offset	Description
	00018000	An 8x8 font that comes in three different shades of grey.
	0002656E	Smoke effects. Their VRAM spot would be overwritten by the Lamppost in the final.
	00026672	Water splash effects for Labyrinth Zone that go unused due to a lack of water. In this prototype, the splash has simpler shading and uses Sonic's palette.
	000267D4	Sparkle effects.
	00026BF6	Small flame effects.
	0002E6C8	Combo bonuses awarded from enemies and breakable objects. All numbers are loaded in VRAM in preparation for combos, but defeating enemies consecutively only awards 100 points in this build.
	00060864	An assortment of parts for the Egg Mobile. 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. The second image is an attempt at assembling the spring attachment.
	0006512E	Skull block for the Special Stage.
	000651FE	"U"/magnet block for the Special Stage.
	00065B76	A Chaos Emerald for the Special Stage.
	0006C8A0	An unused animation frame for the UFOs in Marble Zone. Use PAR code 11430:0006 to restore it in the animation script.

Objects

Placeable in edit mode

Art	ID	Description
		Static monitor that does nothing when broken.
	4F	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.
		Roller enemies for Spring Yard Zone. They are fully functional, and use the second palette line, making them look purple and yellow.
	5E	Seesaws for Star Light Zone. While fully functional, they don't have the spike ball that helps propel Sonic into the air.

Others

Art	ID	Description
	02-03	Two graphicless objects that date back to the earliest stages of the game's development in February 1990. Object ID 2 is a "pulsating" object, and 3 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.
	04	An animated object similar to ID 3, which can be placed anywhere on the X axis but has a fixed Y axis.
	05	An invisible object.
	06	An object that follows the HUD.
	1B	A static, collisionless object with two variations, but no corresponding graphics. In the final game, this object was replaced with the water surface object for Labyrinth Zone.
	1D	An unused switch that acts like any other switch that opens a closed passage. It remains unused in the final game.
	1E	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.
	20	The bombs dropped by the Ball Hog.
	2A	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. In the final game, this object was replaced with the one-way doors for Scrap Brain Zone.
	2C	Jaws enemies for Labyrinth Zone, which exist in the object table but go unreferenced. They are fully functional.
	2D	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.
	4B	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 warping effect has an object ID of 4A.

Audio

Music

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

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

There is an alternate palette intended for Green Hill Zone that exists in the ROM, but is not normally used. By changing ROM address 1AF6 to 0001D 9C and 1AFE to 0001D 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.

Sparkling Zone early object layout

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 000729CA. To access it, change ROM address 00070040 to 00029 CA.

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