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Prototype Zones/Chemical Plant

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Chemical Plant Zone

Nick Arcade Prototype

Chemical Plant Zone was in a much earlier stage of development here than in the later beta.

Act 1

Chemical Plant Zone Act 1: Nick Arcade Prototype
Cpz1 mapd small.png
Chemical Plant Zone Act 1: Final
Cpz1 mapf small.png
In the final, some adjustments have been made to make the level longer. The design in this beta is fairly complete, it just doesn't work yet.

Simon Wai Prototype

Chemical Plant is mostly completed, with little differences from the final version. Like several other zones, Chemical Plant here has no enemies.

Act 1

Act 2

Leftover Data

When Sega was writing this prototype's data to the ROM chip, some existing data from a previous build wasn't overwritten. After hardcore hacking of the ROM by Nemesis (who has pretty much dissected the ROM inside out -- check his website), it's found out that some tiles in CPZ were a little bit different in an earlier prototype.

Nemesis explained how data in the ROM could be leftover:

You see when the rom was in the development stage, the sonic team would've used flashcarts to copy the data onto for test purposes, and for distribution. I assumed the way this would work was that the rom would be compiled on the computer, and the compiled rom would be copied onto the cartridge. I can see now that it was compiled directly onto the cart. The result this had was any sections of the flashcart that didn't actually have to be modified, weren't modified. Now on a final release cart, this would've simply left a block of data all filled with FF's, becuase that's the canvas value if you will. On the flashcart, it was simply whatever junk was there before, and in this case that "junk" is leftover data from an earlier version of S2, even earlier than our beta.

—Nemesis, ROM Hacker, Area 51 phpBB (defunct)

All that savestate is is a direct rip of the block mappings that were buried in the rom, and the patterns to go with them being loaded into the VRAM. As you can see (or at least Iceknight can see) there are quite a few differences spread all through it. Make a CPZ savestate and compare the block mappings in hex (2478-A477: 128x128 block mappings, B478-CE77: 16x16 block mappings) and compare the patterns in the debug viewer and you'll see the differences.

—Nemesis, ROM Hacker, Area 51 phpBB (defunct)

Hey, remember that one of the buildings in the background was smaller in the Nick Arcade version...? Well, these graphics seem to come from an EARLIER version than that one!!

Not only that building is completely MISSING, but there's another one that can't be found there as well, unlike in the N.A. beta

—ICEknight, ROM Hacker, Area 51 phpBB (defunct)

ICEknight has put together six savestates, incorporating the old tiles into the actual level.

Ok, I've ported those 16x16 and 128x128 patterns into the beta Chemical Plant. It can't show us exactly how the early CPZ was, but you can see those parts that didn't exist yet because the needed patterns weren't made yet.

A little description of the savestates inside...

gs0: A normal CPZ beta savestate. gs1: Same savestate but with Nemesis' graphics and 16x16s. You can see that some places didn't exist yet because of the missing graphics. gs2: Same thing but with the 128x128s too. There's a lot of places that make no sense at all because the original level was planned to be different. You may even see an unused part of background where it obviously shouldn't be.

You should move around if you don't want to see any garbled graphics.

Then, if you just want a quick compare of the backgrounds:

gs7: Normal CPZ savestate. gs8: CPZ savestate in the same place, with old graphics and 16x16s, but new 128x128s. The buildings that didn't exist in the older version are using the wrong graphics because their graphics weren't there yet. gs9: CPZ savestate in the same place with old graphics, 16x16s and 128x128s. You will see how the older background looked like. (missing buildings)

—ICEknight, ROM Hacker, Area 51 phpBB (defunct)