Sonic CD's Mysterious Cut R2 Level Discussion - Post Origins Edition

An official Mirage Saloon Bad Future

 

I can't answer definitively, but there are quite a few plausible reasons for this. First of all, S2 style 2P mode requires the use of interlaced mode, and all tiles (including sprites) have to be 8x16 instead of 8x8. Unless the levels were designed with such a tile arrangement in mind, they'd have to be totally redone. It also has a limit to the number of objects that can be in a certain space. Furthermore, there's the issue that the S3 zones are huge and would not make very captivating races, not to mention it's always streaming data such as portions of the level chunks, different graphics (big ring for instance). AIZ1 would be impossible to have in its entirety, once the level gets set on fire, it actually loads a completely different level layout and set of graphics - if a player was still in the non-fire part of the level, what do you do? They probably also weren't fond of the squishing and flickering inherent with the interlaced mode.

 

I feel it might be a good idea to move all these posts unrelated to R2 to a new thread for development mysteries in general.

 

Sonic CD was released in September 1993. So, I am going to call September 2023 "Sonic CD Month".
Also, I would like to conclude my research on Round 2.
In short: the concept of Dubious Depths was probably merged with Tidal Tempest (Good Future), which in turn was developed further in Botanic Base.

(floor of the same color; machinery with tubes; plants)

Some thoughts: Dubious Depths is a concept of a level with rainbow waterfalls. It evolved into Tidal Tempest (Good Future). Earliest known version of CD Sonic has Salad Plain, which is more like Good Future of Palmtree Panic in the final game. It's possible that a certain time period was created for a level and then used in place of another period. In case with R2 and R4, one variant of Dubious Depths could have been moved to Good Future of Tidal Tempest. Both names fit the level with a lot of water.
At the beginning of TT, you are not quite sure what waits down there, and then Sonic explores the depths... Personally, I had some doubts during my first walkthrough of that zone. Should Sonic explore the deep parts of the stage or it's better to stay on upper levels? Well, Dubious Depths is really what you can call Round 4.

Previously, I mentioned that some people from the development team also helped to make Knuckles Chaotix. And that game shares some similar ideas with CD (also mentioned earlier). Well, they probably thought that there was a nice idea of a zone with plants in special containers and rainbow colored waterfalls. But it was created only partially in form of Tidal Tempest. That's why the team developed it further as Botanic Base.
Concept art with rainbow waterfalls has multiple levels / floors. And that's what Chaotix is known for – vertical exploration.
The name Ridicule Root fits that stage as well. There is a ridiculous amount of plants and, consequently, roots.
We also know about a place in D.A. Garden map of Sonic CD, which looks like a forest. It probably covers a botanic base of sorts. Well, there could be a hidden palace of nature, with a lot of greenery and birds singing... Which reminds me of music for Round 2. It's a perfect soundtrack for a kind of stage I'm writing here about.

 

I wonder if that's why it was 'slow'... it was trying to show off vertical exploration on the SEGA Mega CD hardware, like Nintendo with Super Mario Bros. 2, but couldn't make it work with, y'know, gravity and they decided against it...

 

Why would they be showing off vertical scrolling as a hardware feature? SMB2/DDP did it because there were no vertical scrolling levels in SMB1 due to hardware limitations, but all of Sonic 1's levels were already bi-directional scrolling maps, and the Mega Drive had no trouble accomplishing tile scrolling on either 2D axis.

 

What does the Sega CD hardware have to do with it, though?

 

That rainbow aqueduct concept art barely shows anything but a ramp that could be straight out of the end of Chemical Plant Zone 1’s layout. I don’t think it shows much verticality.

 

The scale. Most of the Mega Drive games seem to be rather limited in how high the maps go, even Sonic the Hedgehog 3 most of their large level scales involve the map wrapping back around on itself and teleporting you from the top to the bottom or vice versa to get around some sort of limitation, which I recall was also in the BETA map of Hidden Palace Zone in Sonic the Hedgehog 2. Sonic the Hedgehog CD's levels, meanwhile, are massive.

Most games of the time would be developed to show off the hardware's capabilities. Sonic was developed to show the Mega Drive was faster than the NES, Super Mario Bros. was developed to show smooth horizontal scrolling on the NES, then Super Mario Bros. 2 was intended to show off vertical scrolling before they scrapped the engine, then reused it for Yume Kōjō: Doki Doki Panic, then Super Mario Bros. 3 was a marriage of both, etc.

With first party companies, it's common practice for them to develop something to show the console's capabilities off, Sonic the Hedgehog CD is no exception with the grand scale backgrounds, Mode 7 scaling in the Special Stages, etcetc.

 

Neither the Sega CD nor the 32X really add anything for vertical capabilities, though. Sonic CD's and Chaotix's stages use the Genesis for rendering them. Sonic CD is only ever using the Sega CD during stages to play CD music and 8 channel PCM audio. Chaotix only uses the 32X to render sprites, the 3D special stages and bonus stages, and other effects, but the base stages are all done on the Genesis. And just to note, the Sega CD's scaling and rotation capabilities work by transforming an image and storing it in a memory buffer that is transferred to the Genesis' VRAM. The only reason why Sonic CD is able to hold all those large levels is due to being able to load one stage at a time in memory from a CD. Chaotix, however, fits in a 3 MiB ROM just fine.

Back in 2020, I made a ROM with a standalone Palmtree Panic Act 1 Present. It works exactly like in the original bar the music and sampled SFX. I also made this ROM (debug version) with all of the stages, although at the time I didn't realize I went over the size limit for the mapper (32 MiB versus the 36 MiB I put, whoops), so some of the Metallic Madness stages aren't really gonna load, I don't think (well, BlastEm at least loads them). The only other thing that doesn't really work is the glass bumpers in Collision Chaos, since it relies on the chunks being stored in RAM instead of ROM.

Point is, though, the Sega CD hardware doesn't really have much to do with the size of the stages, and can run just fine on stock Genesis hardware. In fact, fun fact, Sonic CD basically just uses Sonic 1's engine, and even the tallest stage in Sonic CD can be run on Sonic 1's engine on the Genesis. Making them even taller is really just a matter of redoing some calculates for retrieving stage data to go further and making sure the memory space is there to hold the extra data, and it wouldn't really impact performance.

The real reason why such huge stages weren't typically done was because of memory limitations. Simply put, not enough storage to hold such large levels. Games back then I believe were allocated a size limit for their game, and the more large the ROM chip, the more expensive it would be to manufacture and sell. Sonic 1 was given 512 KiB, Sonic 2 was given 1 MiB, Sonic 3 Alone and Sonic & Knuckles were both given 2 MiB. Theoretically, without such constraints, even the NES could render some MASSIVELY sized stages, because all it really took to render them was to load in new rows/columns of tiles as the stage was scrolled. Hell, most NES games use additional hardware to do bankswitching, because the stock allocation for ROM in memory was so low.

 

No matter what "conclusions" are brought, they are still theories nonetheless. Nobody knows what R2 looked like beyond a couple drawings. And since the video is apparently questionable, I think there's even less to conclude than we thought we had a few weeks ago.

Just saying this because some folks read this, go to other websites like YouTube, and start spewing stuff that's clearly wrong to any of us who know better. I'm not a disinformation nazi; say whatever you believe to be true. But let's add clarity to it by stating "you don't know what you don't know".

 

That “R2” video could be more of Metallic Madness actually, if the antlions were moved there before the video segments were commissioned. The Good Future background kind of fits.

 

I really don't think that clip has anything to do with the good futures of TT or MM. Yeah, they all have technology and vegetation, but that's where the similarities end.

The aforementioned good futures depict a well-maintained technological structure adorned with plants, while the video shows decaying abandoned ruins that are being reclaimed by nature. They're basically polar opposites.

 

Yes, TopBull also mentioned this.
Looking through this topic, I notice that we share some similar thoughts.
But mostly we have only theories, as there is not a single picture of R2 for now. After 30 years. Why this stuff has to be mysterious for so long?
Animated sequence was some kind of a clue... But it did not look anything like the waterfall drawing... And, after Ohshima's message, what we are left with? Only that drawing.
Nishimura does not recognize / remember this picture; Taxman mentioned it's related to R2. That's all.
No mock-ups, no title cards like the one for Salad Plain.
So, if it was only a concept art ("image visual", according to Nishimura), than which one exactly? We know about only 2 pictures made for levels in Sonic CD: Dubious Depths and Stardust Speedway. And how can you come to conclusion that a level "doesn't match Sonic's speed" if it only exists in a form of a drawing? A playable demo is required for that. Designer of Dubious Depths made some work for the stage, before the team decided it was not good enough, right?
You can't just look at an artwork and say: "Oh, it will be too slow for Sonic / there won't be enough space for this on CD."
It went as far as: recording music; making sprites for badniks and boss; listing Round 2 in level select; creating animated sequence based on Antlion's design and (possibly) another artwork we don't know of.
Even after the game's release, Dubious Depths theme was remixed on the album by Hataya and Ogata more than any other level's music. I mean, this composition is echoing through many parts of the album. Was it an attempt to make up for unused Past and Future themes from a version of the game?
A prototype from early 1993 can provide answers for many of those questions, I think. Because the one from December 1992 is very intriguing. It's like a trailer for some big production: "Look, we have a different name for Round 1; its Past music is in CD-audio quality; Round 2 is there in the list... but you can't access it or at least take a look at its name and title card. Wait till next version!"
So, there are these sources of new information from now on:
1. Prototypes.
2.
3. Developers' messages / posts.
4. Releases from SEGA: artbooks and compilations with previously unreleased materials.
We know about some concept art's existence only from videos: Sonic and Knuckles Rock The Rock; Sonic CD developer diary. Those ones feature glimpses of "Temple in the sky", winter level, rainbow waterfall stage, Stardust Speedway Zone.
Some of the art from Sonic 1, 2, 3 and Knuckles also showed up in Tokyo Joypolis event for Sonic's 20th Anniversary. But what about Sonic CD? We have characters / badnik / boss designs, a map, some storyboards... The actual level concepts with annotations would be quite useful. Like: "This one we did for Crazy Toy Box, which ended up being Wacky Workbench Zone. The toy theme is still present in that stage's Good Future".
Wait, I missed option 2 while writing about finding sources of information. Don't know what other option we have. You say!

 

Everyone always forgets Labyrinth Zone, especially the boss where you chase Eggman through a climb so long it's no wonder you end up in the sky afterwards. Yes, it's done with wrapping, but given how nobody seems to mention it I'm guessing not a lot of people noticed.

Also I'm pretty sure Sonic 3's levels are larger than Sonic CD's even ignoring the wrapping.

 

Sonic 3K's layouts generally start with 64 pointers to each row of chunks, 32 pointers for the foreground, and 32 pointers for the background. So with 128x128 chunks, that gets you a maximum height of 4096 pixels, which is twice the height of stages in Sonic 1, 2, and CD (2048 pixels). It also has an extra variable that can basically put a more strict limit for the height by applying an AND mask to the row index (IceCap act 1 and Sandopolis act 2 set it to $3C, for instance, instead of the normal $7C, so the height is halved, getting you 2048 pixels).

The format is actually easily expandable with its use of pointers and masking variable instead of hardcoding it to 16384x2048 like Sonic 1, 2, and CD do. If you can allocate more memory to hold the layout data, you can store more pointers, and therefore increase the height even further, and you won't even really have to modify the game engine to account for it. Just make sure that the masking variable accounts for it.

In fact, most Sonic 3K stages are taller than 2048 pixels. Hell, Marble Garden Act 1 makes full use of the 4096 pixels and also does wrapping. I think the reason Sonic CD stages feel taller is because you tend to have more room to travel vertically in them compared to the other games, given the illusion of a greater height than it really is. Also having taken a look at Chaotix's stages, yeah they can get as tall as 4096 pixels, but their also not very wide at all. Hell, Green Hill Act 1 is wider than the widest Chaotix stage!

So yeah, Sonic 3K pretty much beats out the rest of the classic games in terms of stage size, and that's just on the Genesis alone. If you want to be able to confirm this information yourself, you can take a look at the map rips on Retro's wiki and see the image height for each rip. The raw map rips aren't scaled, so you'll get their true sizes.

Bonus fun fact: it seems that Sonic CD stages were gonna be twice the height of Sonic 1 stages, because they doubled the buffer for stage layouts in RAM and applied a larger AND mask for wrapping (for stages outside of Tidal Tempest). However, they never got around to utilizing it, so half of the buffer goes unused.

 

Absolutely, and I'll explain further: the anthill approach to level design in S3&K made it so that a) you get many mini-stages in a single stage, and the distance between the bottom and upper parts of these mini-stages feel like much less than 2048 pixels, and b) these mini-stages have similar structures and elements, just distributed differently and with gimmicks/set pieces to hallmark some sections. The big differences are between Act 1 and Act 2, usually. Due to all this, the stages not very easily backtrackable, if they can be backtracked at all.

Sonic CD, in turn, has you constantly traversing across upper and bottom zones of the stage, sometimes forcibly so, and the zones are usually very, very different: Collision Chaos isn't actually all that bouncy in its lowest areas, whereas the upper parts of it are basically smaller chunks all throughout, and most of them make Sonic bounce off of them. Couple that with the extreme amount of springs that launch you upward in Sonic CD so that you get to at least see how the upper parts are like, and the fact that they are and must by definition be backtrackable, and you get the impression that the levels are incredibly tall.

Circling back to R2, this is what makes me believe they wouldn't make a stage with an Act 1 above ground and an underground Act 2. That's what S3&K would do. It makes more sense to me to imagine an R2 with canopies at the top and tree-like structures made of small platforms from which it's easy to fall -- maybe they'd phase out like Palmtree Panic's or something --, and ruins at the bottom with traps, roots that slow you down (like Mushroom Hill's vines), and probably a lot f springs to launch you to the air.

Which is also why I don't believe it would've been scrapped before they even designed the maps for the same reasons why the rest of the game is the way it is, by the way. At this point I'm skeptic any concepts from R2 were used elsewhere. The stage was scrapped far too early, very little material was ever made and what we know/can imagine from the workflow and pipeline accounts for it. There seems to be barely any mystery left to it because there isn't anything else to be found.

 

I recall reading that the PC port team noticed this and halved the buffer.

 

Sidenote: would it have been possible to use the second half of the buffer to preload a different timezone for the same level? That would’ve been a cool way to get faster time travel transitions (just warp sonic’s y by a fixed offset), but I wouldn’t know if it could be done.

 

I don't know, I think that may be an issue for the Present as you wouldn't know whether to include the Past or one of the Futures in the buffer? I also don't think it includes the actual tiles, just the data on where to place them if I'm reading right.