Leftovers

This is a sub-page of Proto:Sonic the Hedgehog 2 (Genesis)/Nick Arcade Prototype.

This page is rather stubbly and could use some expansion.
Are you a bad enough dude to rescue this article?

To do:
Everything. Disassembly is here: https://github.com/AlexField442/Sonic-2-Nick-Arcade-Disassembly

Developer text, early level layouts, and more.

Unique#

Offset	Compression	Description
0x1C400	None	An 8BPP image of a tiled map. The bottom row of tiles has been overwritten with other data. Given the formatting of the image and the fact that Sonic 2 had been developed on Amiga computers, this was likely just a scribble that somehow got compiled with the game. Its proper palette is unknown. Colors have been added for illustrative purposes. (Source: ICEknight)
0x30000	None	A JIS X 0201 character set (minus katakana characters), including control characters. It is unknown if this was meant for Sonic 2 development, or if it's residual data left on the cartridge from something else.

Sonic 1 Objects#

While a number of assets from Sonic 1 are used in this build, a bunch of them don't appear. Some don't have their graphics, while others do but simply don't have them loaded in.

Name	Graphic	Object Offset	Graphic Offset	Notes
Crabmeat	I walk, then shoot missiles from my hands. 'Nuff said.	0x0A0D0	0xABC34	While Crabmeat is used in Green Hill Zone, its art never gets loaded in.
Buzz Bomber		0x0A408	0xAC122	Suffers the same fate as Crabmeat: the object is loaded in Green Hill, but not the art.
Newtron		0x0EBB8	0xADA3A	Suffers the same fate as Crabmeat and Buzz Bomber.
Motobug		0x0F248	0xAD7B0	The Motobug is a bit different, though, as its art does get loaded in Green Hill... though it's quickly overwritten by the invincibility star graphics.
Green Hill bridge		0x07BA0	0xA3B2A	This bridge interestingly has its art loaded in... although it's shortly overwritten by the shield graphics.
Helix of Spikes		0x0866C	0xA4010	The helix of spikes suffer from the same fate as most of the other Green Hill assets. However, its alternative graphics are still here.
Helix of Spikes (with pole)			0xA3DFC	Even after being unused in Sonic 1, they're still present here.
Breakable wall		0x0C8C4	0xA426A	Suffers the same fate as Crabmeat, Buzz Bomber, and Newtron.
Wrecking ball		0x190E6	0xA3C5E	Suffers from the same fate as most of the Green Hill badniks.
Swinging platform		0x08204	0xA3A10	Suffers from the same fate as Motobug.
Caterkiller			0xAEDFA	Has no remnants of mappings or coding left, but its graphics are still lying around.
Basaran			0xAE440	Suffers from the same fate as Caterkiller.
Splats			0xAE73C	Surprisingly, an unused badnik's graphics from Sonic 1 made it into this build, though it still has no code or mappings.
Roller			0xAD282	Sadly, we don't get to see this guy in action, as his code and mappings were unfortunately removed.
Yadrin			0xAE058	Only present as graphics. Its coding and mappings were long since removed.
Jawz		0x0B7DE	0xAD002	This one is entirely different from the Green Hill badniks. Jawz is never used in this build, but its coding is still present.
Burrobot			0xAC6B0	Burrobot's mappings and code aren't present in the ROM, but its graphics are still here.
Orbinaut			0xAEC1C	Suffers from the same fate as Burrobot.
Bomb			0xAE984	Suffers from the same fate as Burrobot and Orbinaut.
Ballhog		0x0965C (Ballhog) 0x09730 (Ballhog Bomb)	0xAB874	Ballhog (and in extent, its bomb) suffers from the same fate as Jawz.
Sonic on the Continue Screen			0xB0692	Despite the Continue screen being removed, the graphics for it are still present. Other graphics (like "CONTINUE" and the countdown) are also present in the ROM.
Mini Sonic	Aww, he's so small!		0xB0692	The sprites for the Continue in the Sonic 1 Special Stage results screen are still present within the ROM.
TRY AGAIN text			0xE0180	Remnants of the TRY AGAIN text. Due to being cut off halfway, it is impossible to view with graphic editors. No coding for the screen (nor the credits, for that matter) are left in the ROM.
Flowers			0xE05D2	Both the Kosinski and Nemesis-compressed flower graphics for the ending are here.
Sonic Team Presents and Credits		0x185E0	0xE0DEA	The credits and Sonic Team Presents mappings are interestingly still present within the ROM, despite neither of the sequences being coded in.
"SONIC THE HEDGEHOG" ending logo			0xE13E8	The Sonic the Hedgehog logo from the ending sequence. This is the last thing in the ROM before the ToeJam & Earl overdump begins.

A leftover level layout also made it into this prototype, albeit only a straight line of Chunk $6E.

Misc. Leftovers/Earlier Versions of Objects#

To do:
Get some more objects documented here, if there are any.

Inside the ROM, mixed in with the symbol tables and debug mode source code is what appears to be leftover RAM contents from the assembler that includes additional symbols, and also assembled code. What should be noted is that the data is from a previous build (CES), and some objects do indeed have different code.

Emerald Hill Zone Boss#

Watch on YouTubeDifferences include only 2 hit points, different positioning, a lack of hitbox for the drill, and a weird bobbing movement for the ship's body. The wheels also do not detect floor collision until they fall off the body.

"Overdump" Data Leftovers#

Leftover data from ToeJam & Earl is present from 0xE1670 until the end of the ROM, but contains no differences from its final counterpart. Additional info on overdump content can be found here.