Sonic 3 - A Speculated Development History

Many have known and safely assumed, even since we were young, that Sonic and Knuckles levels were intended for Sonic 3. The recent release of the prototypes proves this. As is now known, there were three versions of Sonic 3 in development – Sonic 3A, which is Sonic 3 Standalone, Sonic 3B, which is Sonic and Knuckles standalone, and Sonic 3C, which is both games merged into one, but without the use of lock-on technology.

Based on my own speculation, some research, and some assumptions, I've concluded that "Sonic 3C" was the original route of the game, which has been documented in the past. However, fairly early in the development process, this game was split into Sonic 3A, which was completed as Sonic 3, while Sonic 3C continued its development fairly late into the development cycle, with Sonic 3B not appearing until months after the original split occurred.

Build Dates and ROM Header Dates
Based on the dates of the Sonic 3 and Sonic and Knuckles ROMs stored within the header information, one might assume that development on Sonic 3, as we know it, began in November of 1993, and Sonic and Knuckles in June of 1994. The Sonic and Knuckles “start date” is confirmed by the Sonic and Knuckles 0606 prototype, as it is the first known prototype of Sonic and Knuckles in which the game is playable by itself, and as the date suggests, was built in June, 1994. The previous Sonic and Knuckles prototype (0525) is a crude attempt at "lock-on", and is entirely dependent on the Sonic 3 data to be able to run. One can then also assume that the actual split occurred in November, 1993, giving Sonic Team the remainder of that November, December, and January to finalize "Sonic 3A", as it was released on February 2, 1994. (It is also my personal speculation that the 2-player aspect was added during this time.)

Level Order and Music Order
Anyone can see that by entering the Sonic 3 level select that there are clearly three Sonic and Knuckles specific zones listed – Flying Battery, Mushroom Valley (Hill), and Sandopolis. One can also see that all of the Sonic and Knuckles zone music was already in the Sonic 3 ROM.

Code (Text):

1. Sound     Sonic & Knuckles Zone
2. -----     ----------------------
3. 09        Flying Battery Act 1
4. 0A        Flying Battery Act 2
5. 0F        Mushroom Hill Act 1
6. 10        Mushroom Hill Act 2
7. 11        Sandopolis Act 1
8. 12        Sandopolis Act 2
9. 13        Lava Reef Act 1
10. 14        Lava Reef Act 2/Hidden Palace
11. 15        Sky Sanctuary
12. 16        Death Egg Act 1
13. 17        Death Egg Act 2

The order of the levels in the game corresponds with the order of the music, including the "Lost" levels. As the level select in Sonic 3 shows, Flying Battery was slotted as the fifth level in the game (Level 04 00 and 04 01). The order of the music in the sound test corresponds with this.

In later builds of Sonic 3C and Sonic & Knuckles, including the final release of Sonic 3 & Knuckles (Lock On), Flying Battery's music is the only music out of order with the final level order. It still falls in line with its old slot. Most of the rest of the game is neatly organized, keeping the music in the same order as the levels/acts.

Title Cards and Flying Battery
Some basic hacking can allow you to enter the Sonic and Knuckles levels within Sonic 3, though none are even remotely playable; in fact, entering each level locks the emulator. The only title card that loads correctly is Flying Battery. More advanced hackers have shown that the Flying Battery Act 2 boss data is still contained within Sonic 3, which shows that at the time Sonic 3 was split into two separate projects, development on Flying Battery was pretty far. Mushroom Valley and Sandopolis's title cards do not load correctly, though reading through some glitches, one can see that it does try to display it correctly (I.e., trying to display Valley in Mushroom Valley). Just the name "Mushroom Valley" indicates that at the time Sonic 3 was spun into Sonic 3A, it was fairly early in the development process, as shown above, November of 1993. Further hacking can allow us entry into Lava Reef, Sky Sanctuary, Death Egg, and Doomsday, all of which show glitches in the title cards, but it is easy to tell what it is supposed to be. This shows that the majority of the story line and level order was already in place by the time the split occurred. One can also speculate that the level order was changed, adding Flying Battery to the Sonic and Knuckles line-up, to even out the number of levels in each game, a decision that was likely also made in November, 1993, when the split likely took place.

Hidden Palace
Hidden Palace was added later in the development of the game, as can be illustrated by the Sonic 3C 0408 prototype. Hidden Palace is available (Lava Reef Act 4), but 1) not accessible without debug, and 2) comes up as Sky Sanctuary Act 1, whereas Sky Sanctuary Acts 1 and 2 in the level select both load and Act 2 title card.
I allowed Sonic 3 to load Hidden Palace's level slot (16 00), and it loaded a zone that played the Blue Sphere Special Stage music with Angel Island's tiles. There are other empty level slots that do the same thing, which proves that Hidden Palace was not being visibly developed by the time the split took place.

Lock-on Technology
From the prototypes that we have access to, "Lock-on" technology made its debut on May 24, 1994 with a release of Knuckles in Sonic 2. An extremely bare-bones version of Sonic and Knuckles is present in this game, unplayable on its own if you split the ROMs. Sonic 3 and Knuckles "Lock-on" made its debut the very next day, also with an unplayable version of Sonic and Knuckles contained within the ROM, in fact, the same version of Sonic and Knuckles as found in the May 24th Sonic 2 "Lock-on". The Sonic 3 Final ROM is also present, providing the much needed Sonic 3 data to allow this ROM to boot, let alone be playable.?

Summary
In summary, Sonic 3's development began as a full "Sonic 3 and Knuckles", so to speak, with a level order of:

1 - Angel Island
2 - Hydrocity
3 - Marble Garden
4 - Carnival Night
5 - Flying Battery
6 - Ice Cap
7 - Launch Base
8 - Mushroom Valley
9 - Sandopolis
10 - Lava Reef
11 - Sky Sanctuary
12 - Death Egg
13 - Doomsday

In November, 1993, the game was split into two – Sonic 3A, which evolved into Sonic 3 as we know it today, and Sonic 3B, which eventually turned into Sonic and Knuckles, however, the actual split of Sonic and Knuckles did not occur until June, 1994. Prior to that, development of Sonic 3C, the original game concept, was continued, and was officially scrapped as a single game in late May, 1994 when "Lock-on" technology made its debut, six months after the original split occurred.

 

First, there are not many people who know the build dates of the games off the top of their heads. I was trying to find that information last night but could not. Just out of curiosity, where did you get that info? I looked high and low.

Second, I say S&K was started in June because the first June prototype is the first Sonic and Knuckles proto that is playable by itself, whereas the 525 build does contain an early build of S&K, but is not playable without Sonic 3 data present in the game.

Third, I wasn't making assumptions. I was trying to rationalize with the research I did and the information I found through this research. I may not be entirely correct or I may not be correct at all, but I wasn't going to sit back and hold in my thoughts because I wasn't sure of the validity of them. I am trying to raise points, start discussions, and build. If I was spewing this without trying to do research to back my thoughts, (I.e., Tails being the guardian of the Master Emerald in Sonic 2) then I can understand you being frustrated, but I tried to intelligently form that post with backing research and information. I've been around here long enough to know that some semblance of intelligence is required.