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Proto:Sonic the Hedgehog CD (Sega CD)
This page details one or more prototype versions of Sonic the Hedgehog CD (Sega CD).
- Warning, as there are still people fooled by this: The so-called "409 prototype" is actually a hoax created by Sonic fan scene member Nemesis.
Sonic CD currently has 12 known prototypes, with 9 being made before the Japanese release, and 3 being made for the US/European releases. Because of this, the game's development builds have been split into two.
Contents
Pre-Japanese Release Builds
These builds were made before the Japanese release.
 | v0.02 Dated December 4, 1992. The earliest known build, which was prepared for the Yuusei Sega World event in Japan that month. Predates the period before Sonic CD was delayed from its originally planned March 1993 release. While only two levels are present, the build sheds some light on the game's development. |
 | Prototype 510 Dated May 10, 1993. A rough early build that was dumped by a group called "Sega Extreme" in 2000. |
 | v0.28A Dated May 12, 1993. Similar to 510, with some minor differences. |
 | v0.51 Dated June 21, 1993. The first build with playable Special Stages, as well as the first that can be completed without cheats. |
 | Prototype 712 Dated July 12, 1993, and also known as v0.70. Much more complete, but still unfinished in places. |
 | Prototype 801 Dated August 1, 1993, and also known as v1.05. Just about complete, with only minor differences left. |
Prototype 806
This prototype is documented on Hidden Palace.
Dated August 6, 1993, and also labeled as v1.09, this was created on the same day as the final Japanese release. A close-to-final build which came with cover art and was released as a demo CD in Japan. It only has Palmtree Panic playable by normal means, although the rest of the game can be played with the Level Select code.
A second version was also dumped on October 26, 2019.
Post-Japanese Release Builds
The game is finalized by this point.
Version 1.11
A PAL build dated August 19, 1993. Aside from a slightly different IP loader and Author for the Redbook Audio tracks, it's identical to the final.
Prototype 920
A US build dated September 20, 1993, still with the original soundtrack. As the game was being reviewed for its US release, Sega of America decided to have a new soundtrack composed for that market, which would polarize fans for years to come.
It has the addition of the updated copyright on the title screen and the level-restart code seen in the US final.
Version 1.15
A prerelease build for PAL territories, dated October 13, 1993. The only difference being that the raw redbook audio track data is authored differently, but other than that, it is almost identical to the final US build (although still having the original Japanese soundtrack).
