Sonic the Hedgehog (16-bit)/Hidden content

Unused Artwork

Special Stage Art

Artwork	Name	Description
File:Sprite03.gif	"Zone" Icons	Found in the object list for the special stages, and its graphics found in the ROM, these unused special stage icons have no known use. They're labeled for Zones 1-6, implying that they may have warped you to another Zone from within the special stage as a sort of shortcut.
	1-up Icon	Extra life icon for the special stages. It's listed in the manual for the game, but it never actually appears in any of the special stages. It is, however, fully functional, and you can place it in any special stage, provided you know how to edit them.
	"W" Icon	Strange icon with the letter W on it. Use is unknown, and has no function when placed in-game.

Unused Monitors

Artwork	Name	Description
File:Tv eggman.gif	Robotnik monitor	Does nothing. Is likely intended to hurt the player, as it does in Sonic the Hedgehog 2 (16-bit)'s 2-player mode.
File:Tv goggles.gif	Goggles monitor	The goggles, they do nothing! Most likely went with the unused Goggle graphics found in the ROM.
File:Statictv.gif	Static monitor	Does nothing. Found in various areas of Scrap Brain Zone in areas where the player can not normally access (such as inside walls).
File:Tv super.gif	"S" monitor	Does nothing. This monitor also appears in a Sonic CD prototype, where it grants the player extra speed and invincibility at the same time. Perhaps that was the intended effect here as well? In later Sonic games the monitor was shown to transform the character into Super form as they normally would when they have 50 rings and collected all the emeralds.

Unused Sonic Sprites

Artwork	Description
File:Standair.gif	This sprite shows Sonic standing while gasping for air. This was presumably used in Labyrinth Zone.
	This animation shows Sonic holding his breath while running. It is speculated that this was used during the countdown to signify no air is left for Sonic.
	This unused sliding sprite is similar to the one used in Sonic CD's Wacky Workbench Zone.
	Though this floating sprite is used in Sonic 2, it is not used in Sonic 1 except for during a split second on the "Continue" screen. Note the lack of a stripe on his shoes.
File:Victorypose.gif	As seen in a couple of prototype screenshots in magazines, Sonic appears to be striking a victory pose after passing the sign post.
File:Spin.gif	These spindash-esque sprites were found in the final ROM, but their use is unknown. Two leading theories is that they were used for a move similar to the spindash or that they are animations for some sort of warp movement.
File:Falling.gif	This set of sprites showing Sonic falling or shrinking are not used in the game and their intended use is unknown.

Zone-Specific Art

Artwork	Zone	Description
	Green Hill Zone	The checkered ball seen on the Green Hill Zone Boss appears to have been originally used in Green Hill Zone, as magazine pictures have shown Sonic riding down hills on it.
File:Totem.gif	Green Hill Zone	The two faces pictured here are not in their original palette, but these appear to be an earlier version of the faces on the totem poles of Green Hill Zone.
File:Missingghztiles1.gif	Green Hill Zone	These unused tiles were found in Green Hill Zone's tileset, and appear similar to the areas used in the underground areas of Sonic the Hedgehog (8-bit)'s GHZ. These may have also been used for a cut underground area.
File:Sidespike.gif	Marble Zone	These spikes are horizontal, rather than the vertical spikes used in the final Marble Zone. They are also slightly thinner.
100px	Spring Yard Zone	This unused graphic can be found in the tileset for Spring Yard Zone. It is unused in the final game, and can be found in several prototype screenshots shown in magazine previews.
	Star Light Zone	These lights were found in Star Light Zone's data but not used.
File:Machinparts.gif	Star Light Zone	The three machines shown were found in Star Light Zone's dataset, but not used in the final game. They appear to have been background objects rather than obstacles.

Splats the Bunny

Splats is a prototype badnik from Sonic the Hedgehog which was cut from the final game. Despite not appearing in the game, the badnik appeared in a set of promotional trading cards for the game and was featured in the UK Sonic the Comic. When Nemesis Format was finally cracked in 2002, the sprites were discovered in Sonic 1.

Some controversy has broken out over the true coloring of Splats—though the sprites to the left have Sonic's palette applied to them and the trading card scan appears to have a bluish tint, the quality and validity of the card has been called into question. Other theories to his coloring include purple (for Spring Yard Zone's palette) and green (for Star Light Zone's second palette line.)

Unused Warping Effect

Thought to be the original method of accessing the special stage, this warp effect activates when Sonic touches the area in which the object is placed. Sonic disappears as he runs into it, and a warping noise plays. Sonic then reappears a few seconds later, likely as a method of testing the object.

Goggles

The graphics were found hidden in the ROM. While the actual purpose of the goggles is unknown, it is speculated that they were meant to give Sonic the ability to breathe underwater.

Each frame of the graphic fits together with one of Sonic's poses. For example:

Unused Eggman Graphics

These graphics were found buried in the ROM. Their purpose is unknown, but it is speculated that they may be part of an "alternate ending sequence" in which Eggman explodes in the background while Sonic runs across the ending level in victory.