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The Hidden Palace is a community dedicated to the preservation of video game development media (such as prototypes, hardware, source code, artwork, and more). This website can be utilized as a catalog for the items that we and others are able to collect and share.

If you are interested in contributing, please see our How to Contribute page.

Past news

Jul 6, 2024: Vanished without a Trace - Out of the Vortex for the Sega Mega Drive

Apr 9, 2024: Crash Tag Team Racing (Xbox Prototype)

Jan 21, 2024: Crash Bash and Spyro 3

Jan 1, 2024: New Years 2024 - Sonic Heroes

Dec 25, 2023: A Very Bandicoot Christmas - Crash Bandicoot: Warped Prototype

Nov 24, 2023: 6GUN: BattleBourne's Unreleased PlayStation 2 Game

Oct 31, 2023: Daredevil: The Man Without Fear - Unreleased PlayStation 2 Game

Feb 28, 2023: Phantasy Star Online Prototype

Feb 15, 2023: PSP Release Candidates

Dec 25, 2022: Project Deluge: Xbox 360 and Wii

Dec 9, 2022: Semradical!

Nov 24, 2022: Sega Technical Institute’s Cancelled Segapede

Nov 23, 2022: Sonic 3 and Feel Preproduction VHS Tapes!

Oct 31, 2022: Happy Halloween 2022! Castlevania: Symphony of the Night for the Tiger Game.com!

Jan 1, 2022: New Years 2022!

Nov 13, 2021: Go Go Goemon! Mystical Ninja Goemon Zero

Oct 10, 2021: Mortal Kombat prototype for the Sega Mega Drive

Sep 18, 2021: Project Deluge: Xbox and Dreamcast

Jul 24, 2021: Angels with Burning Hearts: Burning Rangers Prototype

May 1, 2021: Crash Landing

Apr 17, 2021: Project Deluge: PlayStation 1, Saturn, and CD-I (Part 2)

Mar 20, 2021: Project Deluge: PlayStation 2

Jan 1, 2021: Dreams Come True: Sonic 1 (MD) Prototype

(earlier news)

Latest contributed articles

• Hitman 2: Silent Assassin (Feb 11, 2002 prototype) by Funtimeandrefoxy
• Tom Clancy's Splinter Cell: Chaos Theory (Jan 18, 2005 Multiplayer prototype) by Funtimeandrefoxy
• Star Wars: Jedi Knight - Jedi Academy (Aug 8, 2003 prototype) by Dink
• Star Wars: Jedi Knight - Jedi Academy (Jul 2, 2003 prototype) by Dink
• PiRaSoFt by Lemurboy12
• TRPS by Lemurboy12
• ADDICTION by Lemurboy12
• DiGiTaL by Lemurboy12
• Sega Channel (Feb, 1996 prototype) by Missile
• Prototypes by system/Nintendo 64DD by FWKPedia
(more)

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Latest news

Hidden Palace and The Cutting Room Floor present...

Sonic the Hedgehog CD (Dec 4, 1992 prototype)
Sonic the Hedgehog CD (May 12, 1993 prototype)
Sonic the Hedgehog CD (Jun 21, 1993 prototype)
Sonic the Hedgehog CD (Jul 12, 1993 06:37 prototype)
Sonic the Hedgehog CD (Aug 1, 1993 prototype)
Sonic the Hedgehog CD (Aug 6, 1993 16:54 prototype)
Sonic the Hedgehog CD (Aug 19, 1993 prerelease)
Sonic the Hedgehog CD (Oct 13, 1993 prerelease)
Discuss this release on our Discord server!

And watch the Twitch stream as it happened!

Sonic CD, you say?

In the fall of 1991, Yuji Naka (the main programmer on the original Sonic game and one of the series' creators) decided to leave Sega of Japan and move to North America. With one of the series' creators gone to create titles that would be more in tune with what North American audiences were expecting at the time, Sega of Japan decided to create their own line up of Sonic games that would be developed exclusively in Japan. After several attempts at creating games under the Sega Sonic brand for the Arcade market (some which haven't seen the light of day, such as the canceled Sega Sonic Bros), Sega of Japan decided to create a new original Sonic title for the then newly released Mega CD. This project would be designed and directed by Naoto Ohshima, who was another one of the original creators of Sonic.

Rumors of the game had spread around the time of the Summer Consumer Electronic Show (SCES) of 1992, which was held during the last week of May that year. At the same show, Sonic the Hedgehog 2 was shown for the first time on both the Sega Mega Drive and Sega Game Gear. Along with Sonic 2, reports of various images of Sonic floating around on a CD were circulating various video game magazines at the time. Many assumed that this rumored Sonic game was another port of the upcoming sequel, or possibly a port of the first game with Redbook audio and full motion video, but it was soon announced by Sega themselves that it would be a brand new Sonic game instead. During this time, this new rumored title was to be called "Super Sonic" and was mentioned in various video game magazines all throughout 1992. Even the developers working on Sonic the Hedgehog 2 at Sega Technical Institute communicated very little with the Sonic CD team in Japan, so it's somewhat of a mystery as to when development of the Sonic CD as we see it today officially began.

Sonic the Hedgehog 2 was released on November 21, 1992 worldwide. However, people didn't have to wait long as the Mega CD Sonic title was about to be shown for the first time just a few weeks later!

Sonic the Hedgehog CD (then called "CD Sonic the Hedgehog") made its first global debut at the Yuusei Sega World show on December 6th, 1992. The game was on full display and open to the public to play. The game was also showcased with select cells and background paintings that were used during the production of the opening video for the game. The game boasted full motion video sequences, a great soundtrack, and many hours of replayability with the time traveling mechanic. The game was scheduled to be released sometime in Spring the following year. Observant fans might notice that the header on some of the earlier Sonic CD prototypes suggested a potential date of April 1993. Soon after, the game was globally announced worldwide in various magazines around the world from February to April - some previews even using the same prototype that was featured at the Yuusei Sega World show!

However, it wasn't long before the game would be delayed until later in the year. Production problems seem to have occurred sometime after the Yuusei demo, as it's possible that the game simply wasn't ready to be shipped on time. The prototypes that were built after the Yuusei demo, despite featuring all seven zones, are almost unplayable aside from the first three. It wouldn't be until sometime after June that the game would take shape and resemble a complete product. Oddly enough, the game was not present at the SCES that year.

The final Japanese version of the game was completed on August 6th, 1993. The European and North American releases would follow not long after. The game was a minor victory for the moderately successful Mega CD, as it showcased what the console could do at the time. The game would later receive its first port on the PC in 1996, using the original Mega CD version's source code. This port would serve as the basis for the next port that was featured in Sonic Gems Collection, a compilation that was released for the Nintendo GameCube and Sony PlayStation 2. The game would receive a remake in 2011 for various digital markets (such as iOS, Android, XBLA, PSN, Steam etc) by Christian Whitehead (also known as Taxman within the Sonic community).

Like most Sonic games, prototypes have been dumped and circulating for years within the Sonic community. The first prototype to be made available, the '510' prototype, was originally obtained by profund darkness from an eBay seller in Brazil. The original seller sent an ISO/MP3 rip of the prototype he was selling to profund darkness in 2000 and has been one of the earlier prototypes obtained until now. The original prototype has since been sold and the original disc is now lost. Another prototype (dubbed the '712' prototype) was released by PACHUKA sometime in the early 2000s. While originally dumped as a BIN/CUE, the prototype has since been sold and the original disc is now lost as well. Another prototype (dubbed the '920' prototype) was released in the early 2000s by Sutekh, and is a prototype of the North American version. Another authentic Sonic the Hedgehog CD prototype wouldn't be discovered until sometime in late 2017, where a late prototype was purchased by drx and released (which you can find here).

Up until now, these were the only prototypes we had for Sonic the Hedgehog CD...

...until today...

We have recently acquired a lot of several Sonic the Hedgehog CD prototypes! These prototypes span across almost the entire development cycle of Sonic CD, from its earliest days at the Yuusei Sega World show right up to the release of the US version. Every prototype is unique in some way, except for the Aug 1 prototype, which was a 1:1 match to our previous dump. All prototypes were able to be dumped safely with no issue, and each prototype you see here has been tested and is playable. Note, for the best experience, we recommend playing each prototype with the *.cue (not the *img.cue).

Most of the prototypes that were released ages ago were released at a time when proper methods for preserving the contents of the discs hadn't existed, and so most of the prototypes exist in a state that is far from ideal. For instance, the '510' prototype was possibly released with errors that may have gone unnoticed by the user who dumped the prototype. While the other prototypes were eventually dumped as a BIN/CUE, some information might have been lost while using the tools that were available at the time.

Enter Redump.org! As we mentioned in our Medievil release almost a year back, we recently decided to dump all future prototypes using Redump's methods. Since posting the article, we have acquired the necessary hardware and software needed to create more accurate dumps! Our first release with this method, which we haven't announced publicly until now, has been a redump of the Aug 1 prototype of Sonic CD. We dump each prototype we acquire multiple times with different devices and software and compare each dump to search for inconsistencies. Going forward, we would like to dump all prototypes as accurately as possible.

Finally, would like to thank everyone who donated for this release. If it weren't for everyone, this release would never have been possible.

Until next time!