Sonic the Hedgehog (8-bit)/Hidden content

Unused content

Art

Found by contributors here and The Cutting Room Floor.

	Description
	Ancient handled the 8-bit port of Sonic the Hedgehog and it looks like they intended to credit themselves on the title screen. Only Sega gets the credit in the final release.
	This graphic for the Green Hill Zone totem poles is used in the Master System version of the game, but is left unused in the Game Gear version.
	A Green Hill Zone corner tile from the Master System version, left unused on the Game Gear.
	A checkered spike from the Game Gear version of the game.
	Newtron sprites found in the Master System version of Green Hill Zone. While the enemy appears in Jungle Zone, it uses different graphics.
	Batbrain art which appears in the Game Gear version of Green Hill Zone but isn't used. It was probably meant to be in the caves of Act 2. In the 16-bit version this is a normal enemy in Marble Zone, a level not found in this version.
	This appears amongst the object tiles for Bridge Zone, in both the Game Gear and Master System versions. It almost looks like the top is melted.
	Spring in front of checkerboard pattern, and pole in front of sky tiles for Bridge Zone. The bridges in this zone are do not reach sky level. Found in both versions.
	A horizontal spring without grass present, likely meant for act 2 of Jungle Zone. Found in both versions.
	This appears amongst the object tiles for Labyrinth Zone in both the Game Gear and Master System versions. Perhaps it was intended to be a switch-operated door, like the ones in the Mega Drive version.
	Small and big pillars for Labyrinth Zone. No pillars like these exist in the 16-bit version of the level. Found in both versions of the game.
	Slopes and laser turrets for Sky Base Zone act 3. The latter tiles are not in the Game Gear version.
	Chain and unused cannon for Sky Base Zone.
	A prototype shield animation?

Marble Zone music

An 8-bit rendition of the Marble Zone music is present at $CD0A in the Sega Master System ROM. This and the unused sprite of Batbrain suggests that Marble Zone was possibly intended to appear in the 8-bit conversions, but was cut at some point. A ROM image with Green Hill Zone's music replaced with the Marble Zone music is available here.