Sonic Adventure AutoDemo

From Sonic Retro

SA 98 AutoDemo Title.png
Sonic Adventure AutoDemo
Prerelease of: Sonic Adventure
System: Sega Dreamcast
Build date: Oct 18th, 1998
Source: GD-ROM disc
Found by: Orengefox

Sonic Adventure AutoDemo is a Sega Dreamcast disc demonstrating the then-upcoming Sonic Adventure. It was released in small quantities, presumably for Japanese retailers and events to help promote the game - it was never released commercially, nor was it seen outside of Japan.


The AutoDemo cycles through various in-game cutscenes (exclusively in the Japanese voice track) on a loop. It is not playable, but much like the final version of the game the cutscenes are rendered in real time by the Dreamcast hardware. The disc has an internal build date of October 16, 1998, putting it roughly 55 days after Sonic Adventure's unveiling at the Tokyo International Forum (in August 22, 1998) and roughly 49 days before the build date of the game's first release in Japan (December 10, 1998). The disc was dumped and released to the general public on May 21, 2013.

With the aid of hacking, it is possible to break the cycle of cutscenes in the AutoDemo and access a fully-fledged prototype version of Sonic Adventure. Though much of the game is complete, with certain stages (Windy Valley) missing in the build despite the date, there are a multitude of differences to the final version as well as left-over content from previous builds.

For whatever reason, the AutoDemo appears to de-synchronize on emulators. If one was to burn the image to a standard CD-R, only Sonic's demo would have synchronization issues.


Sonic Retro emblem.svg Main article: Sonic Adventure AutoDemo/Comparisons

List of Differences

Adventure Fields

  • Only the Egg Carrier and the Casino area of Station Square can load in the proper objects and textures in-game, because they are the only areas that are used in the Autodemo's cutscenes. The other areas are in the game but are missing objects and textures, and will crash or will send the player back to the title screen if accessed in-game.
  • The reason why is 8C768B38 (2C768B38 for Demul) is set to 5, to prevent it, set it to 4 in Cheat Engine.


Test Level (STG00)

  • This is a series of test levels used to test the game's physics and pathing systems, and were replaced with the Hedgehog Hammer minigame in the final. The file contains three sets of level geometry:
    • The first test level contains structures such as loops and slopes in various configurations. It also has some thin paths and floating platforms. It has three models. This test level will crash the game if the player attempts to load it.
    • The second test level contains structures such as slides and tubes (of which there are many), a pinball-rail-like track, a deep conical region, and an area consisting of wavy slopes. This test level will also crash the game if the player attempts to load it.
    • The third test level tends to crash level viewers and consists of twelve models. It is entirely missing references to textures. It tests paths for scripted sections.
  • Also present in the build are set files for all three test levels. All the set files have the same object layout.
  • At the end of STG00.bin are some strings, alongside what their English translation would be:
    • ジャンプ中にもう一度 ジャンプボタンを押して。 (Press the jump button once more while jumping.)
    • ホーミングアタックよ。 (It's the Homing Attack.)
    • テストメッセージです。 (This is a test message.)
    • ソニックと E-102でだけ出る予定です。 (The plan is to go out with only Sonic and E-102.)
    • ソニックです 音声データは適当です。 (It's Sonic. The voice data is unfinished.)
    • マイルズです ナックルズですです 飽きたので残りは一まとめです。 ("It's Miles It's Knuckles Since I got tired all that's left is a single collection." Of note is that for some reason the trailing "desu" at the end of the "It's Knuckles" portion is here twice.)
    • メッセージ1 メッセージ2 (Message 1 Message 2)

Hot Shelter

  • Is completely missing in this build - no level data whatsoever, aside from initial coordinates for Amy.


Sand Hill

  • This build has a single camera file (CAMSBOARDS.BIN, with the S suffix for Sonic) for Sonic's minigame. In the final, two camera files are used instead.
  • This build also has a single set file (SETSBOARDS.BIN, with the S suffix for Sonic), which is smaller than its corresponding final. In the final game, there are two set files - one for Sonic, one for Tails.

Twinkle Circuit

  • Only level geometry (an early model, like Casinopolis above) is present, and it occupies the slot that Mystic Ruins - The Past occupies in the final. The geometry has small inclined areas that aren't seen anywhere in the final in any course.


  • None of the characters have their appropriate upgrades in any of the in-game cutscenes, except for Gamma occasionally having the Jet Booster (see below).
  • The cutscene where Eggman ambushes Sonic and Tails (Tails version) has several differences:
    • Tails' theme is the backing track for the entire cutscene. In the final, the theme playing in the background is Eggman's.
    • The cutscene takes place at sunset. In the final, it takes place at night.
    • Tails's mouth is modeled differently in his closeup after being gassed by Eggman.
  • The cutscene where Amy first meets E-102 Gamma in the Egg Carrier has several differences:
    • There are item boxes in one of the other cells. In the final, there are no item boxes and a black Chao egg is contained in one of the cells.
    • When Gamma first appears, he is in his normal standing pose. In the final, he is in the "gun held" pose that he has on the character select screen. Because of this, in this prototype his animation momentarily glitches when beginning to turn to his right - he briefly takes on the "gun held" pose before turning.
    • There isn't any odd draw-distance fog in this version, and the lighting is much brighter here.
    • The game can't seem to decide if Gamma has the Jet Booster or not. At the beginning of the scene, he has it, then it disappears when walking to the cell, reappears while he questions Amy, and disappears while glitching out.
    • Likewise, the game can't seem to decide if Gamma has his targeting laser or not. It seems to be tied to the appearance of his Jet Booster, as it disappears when that item disappears.
    • When Amy starts imploring him to help, he backs up. However, his animation in this prototype is actually much smoother than in the final - he moves back more with his backing up animation. In the final, he is inexplicably forced back and then does his backing up animation.
    • Gamma's "glitching out" noises are much louder than his voice.
  • In the cutscene where Amy meets Sonic outside of Casinopolis, the bird's wings are missing.
  • The cutscene where Eggman addresses all the E-100 series has several differences:
    • The lighting is much brighter. This causes issues with the rendering of the E-100 series, primarily faces that appear white due to the lighting.
    • In the final, there are green lights at the corners of the monitors behind Eggman. These are missing here.
  • The cutscene where Gamma steals Froggy from Big at Emerald Coast has several differences:
    • "BIG Fishes at Emerald Coast" is playing in the background. In the final, there is no music.
    • Gamma inexplicably has his Jet Booster upgrade.
    • Big's shaking animation goes on for much shorter here - he shakes and then immediately turns around to face Gamma. In the final he shakes for about a second before turning around.
    • Gamma's idle animation is slower in this scene than in the final.


  • The title screen used in this build has its own filename, DEMO_TITLE.PRS.
  • This build has three text files contained within track01.raw. The three text files are:
    • SONICABS.TXT: Containing "Abstracted by none."
    • SONICBIB.TXT: Containing "Bibliographiced by none."
    • The build has a number of decompressed event files (EVF0800.BIN through EVF0806.BIN); in the final, these are compressed and given different names in the final. EVF0803.BIN is missing, and likely corresponds to a demo for Knuckles as it is also missing in this build.


The hidden wallpaper.
  • Inside track01.iso, there is a folder called EXTRA. Inside the folder is a .bmp wallpaper that was on the Japanese website.

Unused and Leftovers

  • TITLE.PRS is in this build too, but unlike in the final (which shows a title screen for a "beta" labeled version), it shows the TGS '98 version of the title screen!
  • There are unused textures dating back to 1997 saying "GOAL!!" (GOAL_A.PVR, GOAL_B.PVR) and "START!!" (START_A.PVR, START_B.PVR).
  • There are unused graphics that were likely used for mission rankings, like in Sonic Adventure 2. They exist in the final's files as well.
  • An earlier version of the pause screen is included in this build, including assets, but can only be seen in-game via hacking. Only the textures from this survive in the final.
  • Textures for the font used in boss title cards is in a file named 32ASCII.PVR. This file does not exist in the final; the font was moved to another location, likely to texture files for stage objects. The font itself saw some alterations between this build and the final:
    • Q was replaced with the symbol for Delta;
    • X was replaced with the symbol for Epsilon;
    • q was replaced with the symbol for Zeta;
    • x was replaced with the symbol for Alpha (used to designate Zero, which in supplemental material is referred to as E-100 Alpha);
    • The symbol for II (Roman numeral 2) was added at the end of the final font file;
    • The symbol for Beta and the kanji for "revised" (改), both used for E-101 Beta Mk II in the Japanese version of the game, were added to the JP version of the final font file.
  • Likewise, this build has a separate texture for the boss fight HP bar (TARGET_HP.PVR) that doesn't exist in the final; it was likely merged into another set of files instead of being a standalone item.
  • CAM0B00S.BIN is an empty camera file for a cut stage or test stage. Unlike all the other camera and set files in the build, this one uses hexadecimal numbering instead of decimal numbering. It also has the same file date as the camera file used for the test stage (see above), which is also blank. On the other hand, if the filename is read as decimal, it'd be CAM1100S.BIN - this could indicate that it could be for a cut stage, as all versions of the game skip STG11 in their numbering schemes.
  • DROP.PRS is an unused water drop animation.
  • RIPPLE.PRS is an unused water ripple animation, circular and looking like it could go with DROP.PRS. It might be used in the Chaos 0 fight for the rain drops hitting the ground.

Physical scans

Dreamcast, JP
SA AutoDemo Cover.png
SA AutoDemo Disc.png
SA AutoDemo BackCover.png
Manual Back

External links


Sonic Adventure AutoDemo, prototype version of Sonic Adventure
SA 98 AutoDemo Title.png

Main page | Comparisons | Hidden content

Part of Sonic Adventure development

Sonic Adventure / Sonic Adventure DX: Director's Cut
Sonic Adventure title.png

Main page (SADX|2010)
Cheat codes (SADX)
Credits (SADX)

Manuals (SADX)
Promotional material (SADX)
Magazine articles (SADX)
Video coverage

Development (SADX)
Hidden content (SADX)
Bugs (SADX)
Hacking guide

  • Levels
  • Enemies
  • Bosses
  • DLC
  • Story Scripts
  • NPC Scripts
  • Prereleases
  • Media