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 has a ton of available prototypes, including several localization builds.

Pre-Japanese Release Builds

Builds dated prior to the game's Japanese release.

Ver0.02 Dated December 4, 1992. The earliest known build, 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.

Ver0.28A Dated May 12, 1993. Similar to 510, with some minor differences.

Ver0.51 Dated June 21, 1993. Special Stages are now playable, and the game can now (almost) be completed without cheats.

Ver0.70 Dated July 12, 1993. Much more complete, but still unfinished in places.

Ver1.05 Dated August 1, 1993. Just about complete, with only minor differences left.

Ver1.09

  This prototype is documented on Hidden Palace.

Dated August 6, 1993, 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, seemingly for Sega of Europe, was dumped on October 26, 2019.

(Source: BetaArchive, Sonic Retro)

Post-Japanese Release Builds

The game is finalized by this point.

Ver1.11

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

  This prototype is documented on Hidden Palace.

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.

(Source: Sonic Retro, Secrets of Sonic Team, Sonic Cult)

Ver1.15

  This prototype is documented on Hidden Palace.

A pre-release US build dated October 13, 1993, with the only difference being that the raw Redbook Audio track data is authored differently.