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Sonic Adventure (Dreamcast)

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Title Screen

Sonic Adventure

Developer: Sonic Team
Publisher: Sega
Platform: Dreamcast
Released in JP: December 23, 1998
Released in US: September 9, 1999
Released in EU: October 14, 1999
Released in AU: December 3, 1999


AnimationsIcon.png This game has unused animations.
AreasIcon.png This game has unused areas.
CharacterIcon.png This game has unused playable characters.
EnemyIcon.png This game has unused enemies.
ObjectIcon.png This game has unused objects.
MinigameIcon.png This game has unused modes / minigames.
GraphicsIcon.png This game has unused graphics.
ModelsIcon.png This game has unused models.
MovieIcon.png This game has unused cinematics.
MusicIcon.png This game has unused music.
SoundIcon.png This game has unused sounds.
TextIcon.png This game has unused text.
DebugIcon.png This game has debugging material.
LevelSelectIcon.png This game has a hidden level select.
RegionIcon.png This game has regional differences.
Carts.png This game has revisional differences.
BonusIcon.png This game has hidden bonus content.


NotesIcon.png This game has a notes page
ProtoIcon.png This game has a prototype article

Sonic Adventure is the first true 3D Sonic game, with people either saying this killed the series or resurrected it. It's still considered a good game despite it leading towards bad ones like Sonic '06.

It was later re-released with added features on GameCube and Windows as Sonic Adventure DX: Director's Cut.

Sub-Pages

SoundIcon.png
Unused Audio
A whole load of unused voices, with a lot of them referencing features that didn't make it into the final game.
Sa flyingdragon.png
Unused Objects
Sky Chase was going to have a mechanical dragon boss at one point.
SonicAdventure O COWGIRL.png
Version Differences
Sonic Adventure had some major work done over the nine months between the Japanese and Western release.

Unused Graphics

Menus

Title Screen

SonicAdventure BetaTitle.png

A "β version" of the Japanese title screen can be found in TITLE.PRS. This is technically used, but only in the hidden TGS mode.

Coming Soon Screen

SA-ComingSoon.png

A teaser found in COMESOON.PRS, a file only present in the original Japanese version. The Japanese text translates to "Scheduled for end-of-year release".

It was used at the end of stages in prerelease demos, including the AutoDemo.

(Source: Windii (Translation))

Loading Screen

C'MON ALREADY!!!

A loading image that can be found in LOADING.PRS. Like the title screen it's still technically used in-game, but only in the hidden TGS Mode.

Vs. Tails

SonicAdventure VsTails.png

Among the menu graphics for the last completed stage, "Vs. Tails" can be found. As Tails is never fought by any character, it goes unused. It can be found in AVA_STNAM_E.PRS.

HUD

Early Pause Menu

SonicAdventure-hyoji pause1 mockup.png

An early version of the Pause Menu can be found in CON_REGULAR_US.PRS in the original Japanese version of the game. This is a mockup of what the menu looks like put together.

Both this and a Japanese counterpart are in the Autodemo, with the latter being used albeit hidden. In later versions, this file was replaced with CON_REGULAR_E.PRS.

Level Icons

SonicAdventure LevelIcons.png

Icons for the letters S, A, B and C can be found. These were probably intended to be used with an older HUD that can be seen in prerelease materials and the AutoDemo, which contains a "Level" element in the HUD that these letters may have been used for. They can be found in CON_REGULAR.PRS.

Stopwatch Item

Why is it that every stopwatch in the video game universe stops time?

A stopwatch that would have likely frozen the timer and/or enemies, or add time back to the clock in E-102's stages. It can be found in OBJ_REGULAR.PRS.

Tornado 2 Health Bar

Sa tornado2.png

The red "Tornado" life gauge is used in both acts of Sky Chase, despite the fact that a separate life gauge exists for the Tornado 2. As such, this blue "Tornado2" gauge is never used. Both health bars are stored together in the texture file ST_128S_HPGEJI.PVR

Lure Icon

SonicAdventure LureIcon.png

A fishing lure icon that can be found in FISHING.PRS. This icon is used as part of Big's life counter in the AutoDemo.

Misc

Chao Emotes

Chao are very strange creatures...

Other Chao emotions, left out for unknown reasons. They can be found in AL_ICON.PRS.

Realistic Blue Hedgehog

Sega hard at work developing "Sonic 4".

A painting of a blue hedgehog. This picture can also be found in Sonic and the Secret Rings alongside a "making of" video. Neither its purposes nor its intent are known. It can be found in DRAMA0.GIF

Star Panel

SonicAdventureAutodemo StarPanel.png

The star panel seen in various early materials for the game (including the AutoDemo) can still be found in 1ST_READ.BIN. It was used to mark the position the player would land at after finishing a series of jump panels.

Spring Model

SonicAdventure-oldspring.png

A spring model which resembles the spring from Sonic Jam. Neither the model or its ill-fitting texture are used anywhere in the game. Oddly enough, if you apply the Sonic Jam texture to this model, it fits perfectly.

Hmmm...
To do:
Get an image of what it looks like with the Sonic Jam texture applied.
(Source: Sonic Retro)

Hot Shelter Website Screenshot

SonicAdventure BigHotShelter.png

Among the files on the disc used for the Internet pages is this screenshot of Big in Hot Shelter. The screenshot implies it would have been used in one of the website's hint pages, but it's never used.

Adventure Mode

Early Station Square Sky

SonicAdventure EarlySky1.pngSonicAdventure EarlySky2.pngSonicAdventure EarlySky3.png

Early screenshots of the game (as well as the AutoDemo) showed Station Square with a different sky. While the file SS_BG.PVM is used for Station Square's sky in the final game, the images that were used originally can be found in the files SS_FINESKY, SS_NIGHTSKY and SS_YUSKAY_MINI.

City Background

SonicAdventure SonicIntroBG.png

There are two versions of the skyline seen in Sonic's intro in the game's files - one 256×256 version and one 512×512 version. Only the 256×256 version is shown ingame however, meaning this higher quality 512×512 version is never used. It can be found in ICM0001_5.PRS.

Unlocking Sonic

Text for unlocking Sonic can be found:

Now you can play as SONIC!

This is never used as Sonic is unlocked from the start.

Inaccessible Super Sonic Recaps

SonicAdventure SuperSonicRecap.png

On the first playthrough of the story Super Sonic has recap summaries just like every other character, but due to Super Sonic's story never saving after cutscenes, only two of them can ever be seen. This is because Sonic is in the past at these points and the only ways to save the game are to either complete an action stage or obtain the Crystal Ring.

Upon arriving in the past:

I’m Sonic! Sonic the Hedgehog!
When I arrived at Angel Island,
to my surprise I found both Eggman and
Knuckles lying unconscious on the ground.
What did you say?
Chaos is still alive??
…And then all of the sudden
I found myself in another world.
Just like before…!
What is this place!?

After approaching the Knuckles Clan:

I’m Sonic! Sonic the Hedgehog!
In that mysterious world…
I saw a girl…
and many Chao. And an army of warriors
marching towards the Emerald,
Then… It was standing in front of them.
But… who? Who is that girl?

Unused Cutscenes

EV00B3
An unused cutscene can be found for E-102 Gamma that implies it would have been played after failing to complete Final Egg.

EV0134
In the original Japanese version, an unused cutscene for Amy's story can be found. When translated, she says the following:

Japanese Translation
また来ることになるとは思わなかったなぁ… I never thought I'd come back here again...
こんなとこにまだいるのかしらね、あなたの兄弟たち… I wonder if your siblings are still here in a place like this...
ん? Hm?
今、上のほうから声がきこえなかった? Did you hear a voice/cry from above just now?
行ってみよ! Let's go take a look!

The cutscene was intended to play before the battle with ZERO. Not only does Amy never go to this area before fighting ZERO, but it's impossible due to the forced cutscene and the only possible way into the Carrier (Chao Garden warp) being disabled. It does not play if Amy is forced into the area using cheats and was removed from later versions of the game.

(Source: evilhamwizard (Discovery), Windii (Translation))

EV00F6 Cameras
When Sonic enters the Past in Super Sonic's story, the camera appears behind him in the same manner it does when playing normally. However, these aren't actually the correct cameras and the view seen normally is in fact a bug caused by the transition from the previous scene. Through hacking, it's possible to see the correct cameras.

As-is Intended
SonicAdventure PastCamIncorrect1.png
SonicAdventure PastCamCorrect1.png
SonicAdventure PastCamIncorrect2.png
SonicAdventure PastCamCorrect2.png

This bug persisted into the GameCube version, but was fixed in the 2004 PC release and on later ports.

Duplicate Casino Geometry

SonicAdventure CasinoGeometry.png

If the player goes to and leaves the Casino area in Station Square, duplicated geometry of the casino will appear out of bounds in every other part of Station Square. The duplicate has incorrect textures and no collision at all.

(Source: Sonic Retro)

Casinopolis Entrance Camera

SonicAdventure CasinoCamera.png

If the player stands inside the entrance to Casinopolis but not enough to load the stage, the camera slowly pans up to the Casinopolis sign and locks in place until the player leaves the building.

Egg Carrier Boss Arena

SonicAdventure EggCarrierArena.png

In the AutoDemo and earlier versions of the game, the center of the arena used to fight Chaos 6, E101Mk.II and ZERO was raised a lot higher than what can be seen in-game. This appears to be have been a very late decision, as all low-detail models for the Egg Carrier (Sky Chase and Adventure fields) and FMVs use this older design.

Unused Location Flags

There are a small number of flags in the game for certain characters that will open up areas that they usually will never go to:

  • Amy has a flag for opening the door to Casinopolis.
  • Amy has a flag for opening the door to the outer area of Angel Island.
  • Big has a flag that opens the door to the Casino area in the train station.

Flashback Images

Some differences can be seen in the images used for Amy and Gamma's flashbacks, due to being based on/taken using an earlier version of the game:


(Source: PkR @ SonicRetro.org - explanation of cause of Beta's texture error)

Action Stages

Unused Acts

There are a number of empty, unused Acts in the game. Most of these unused acts have files for them such as objects or textures, but the Acts are never used.

  • Hedgehog Hammer has a single unused Act after the one used in-game. The only file for it is its object file (SET0001S.BIN), which contains a single ring at (0,0,0).
  • Hot Shelter has two unused Acts after the three used in-game. These unused acts have no geometry or starting coordinates, but they use the music from Acts 2/3. Act 4 has a single ring present at (0,0,0) but Act 5 has no objects at all.

Start Coordinates

There are many stages in the game that include starting coordinates for characters that don't normally go to that specific stage or act. They're mainly positions used by other characters, but sometimes they're entirely different due to the coordinates being set in an earlier version of the game.

Stage Character Position Notes
Emerald Coast Act 3 Sonic 5815,5,1136 Same as Big
Windy Valley Act 2 Gamma 694,-113,-205 Sonic's starting coordinates from the original version of the stage.
Windy Valley Act 3 Gamma 0,700,0 Sonic's starting coordinates from the original version of the stage.
Casinopolis (All Acts) Everyone N/A Same as Sonic
Red Mountain Act 2 Tails -397,1039,3141 Near the capsule. The game forces him to leave the stage immediately due to only being used for a cutscene.
Sky Deck Act 2 Tails 327,-74,2535 Same as Sonic
Sky Deck Act 3 Tails -1237,15,97 An entirely different spot to Sonic and Knuckles on the edge of the stage.
Lost World Act 1 Knuckles -264,-23,-168 Just below where Sonic starts.
Final Egg Act 1 Gamma 187,-75,957 Used for Sonic in earlier versions/the AutoDemo.
Final Egg Act 2 Amy/Gamma 1060,588,-384 Same as Sonic but facing sideways.
Final Egg Act 3 Amy 1078,15,-830 Used for Sonic in earlier versions/the AutoDemo.
Final Egg Act 4 Sonic/Amy/Gamma 2811,-405,-1001 Black void


Twinkle Circuit Tracks

While only one course is available normally, there are actually 6 courses for Twinkle Circuit in the game. One of these can be played via a VMU download (Samba GP), but the remaining 4 tracks go unused. Interestingly, the course used for Samba GP is actually the third course rather than the second. A "Mercury GP" banner can be found hidden on the game's website, but no downloads for it are known to exist.

(Source: Avento128bits (Video))

Casinopolis Sound Files

In the Japanese version of the game, files containing sound effects and voices (.MLT) for Amy, Big and Gamma in Casinopolis can be found:

  • CASINO_AMY
  • CASINO_AMY_VOICE
  • CASINO_BIG
  • CASINO_BIG_VOICE
  • CASINO_E102
  • CASINO_E102_VOICE

Despite never going to Casinpolis, these extra files allow Amy, Big and Gamma to use their correct sounds for actions such as jumping or attacking. In other versions these files were removed, so the three use Sonic and Tails' sounds and voices instead. None of these files contain idle lines, as those weren't added until later versions.

Alternate NiGHTS Icons

SonicAdventure AltNiGHTSCards.png

The cards in the NiGHTS Pinball area of Casinopolis have a set of alternate designs that never get used. While some cards (NiGHTS and the Nightopian) look similar to the used ones, these versions have stars in the background that aren't present on the regular cards.

Blocked Passage in Casinopolis

Right at the start of "Dilapidated Way" (e.g., the sewers), there's a passage up to the right. Although it's clearly visible, it cannot be accessed due to an invisible wall. It goes on for some time, twisting and turning, but abruptly hits a dead end.

The items you find in the path are different for Sonic and Tails:

  • As Sonic, the path is empty except for two item boxes at the top of the path containing an Extra Life and Speed Shoes.
  • As Tails, the path contains a Lightning Shield box and many trails of rings throughout the path.

From the objects present in the path it was likely intended to have been used as a starting point for Tails.

Icecap Geometry

Leftover geometry from other Acts exist in Icecap that can't be seen normally.

Final Egg Leftovers

Final Egg has some interesting leftovers from earlier stages of development.

There are two paths at the beginning and end of Final Egg that are blocked off by walls ingame, rendering them inaccessible normally:

This stage has an unused 4th Act complete with its own starting coordinates, objects and textures. However, it has no geometry and the object placement (SET1003S.BIN) is a copy of one of the early test stages (SET0000S.BIN), with the only difference being in object IDs.

The Act itself is a leftover from an earlier version of the stage where the map seen in the cutscene before fighting the Egg Viper was part of Final Egg rather than the Egg Viper's map. The second inaccessible area was originally part of the Act transition to this area - in fact, the camera for doing so is still used if the player walks up to the blocked entrance in the final game.

Blocked paths in Sand Hill

There are two forked sections in the rightmost path of Sand Hill that have one path blocked off by large objects. This is due to reusing the same geometry for both forks.

Sky Chase Cannon Failure

When the player gets to the end of Sky Chase 2, they must defeat the Egg Carrier's cannon to complete the stage. However, if the player waits for roughly a minute and a half the cannon will suddenly start to take damage and drain its own health bar, eventually defeating itself without the player needing to do anything.

It's not known why this happens.

Characters

Actions and Animations

Tails has a small number of actions in the game that he never uses as either the player character or while following Sonic:

  • Tails has a working "Pinball mode" for the pinball tables in Casinopolis. However, much like Sonic in the Japanese version of the game, Tails can't shake the table.
  • Jump Panels are fully functional as Tails, whereas Knuckles/Amy get stuck on the second panel and Big/Gamma can't use them at all.

A number of animations in the game go unused. Some are never used because they're never needed, but others aren't used entirely.

  • Sonic, Super Sonic, Tails, Knuckles and Gamma have animations for reverting back to the standing pose from their 'stage clear' ones.
  • Everyone has animations for landing from a fall both normally and while holding an object, but only Gamma's is actually used. Everyone else jumps to the standing pose (aside from Sonic, who uses his 'action' pose).
  • Sonic and Tails are both able to pull objects but neither of them can do so because they never encounter anything that can be pulled.
  • Knuckles has a number of empty animation slots that were formerly used for his early combos - the effects on his hands while performing the moves still exist and can be seen if his punching animation is replaced with one of these slots.
  • Amy has a balancing animation.
  • Super Sonic has animations for bouncing on a spring, despite the Perfect Chaos battle not having any springs.

Eggman and Tikal

The Dr. Eggman and Tikal objects used in cutscenes are actually programmed the same way as the playable characters, and can be played via hacking. They both have only the most basic movement functions, walking and jumping. They can't hurt or get hurt by enemies and obstacles, and cannot run on wind paths and some loops. Pressing the Action button activates free movement mode.

Dying before hitting a checkpoint or changing segments in an Action Stage causes the game to crash, as they do not have starting position lists.

Z Button

By pressing Z, you can make the player turn their head towards the camera. This can be done with anyone aside from Gamma and Super Sonic (though Big will only move his pupils). It works on the character select menu as well, but the only character that will react is Sonic and he'll look to his left instead of at the camera.

While this button was not standard on the official Dreamcast controller, some alternate controllers (such as Sega's Dreamcast Arcade Stick) supported it, and it can be mapped and used in emulators.

Additional Board Controls

SonicAdventure SnowboardSide.png

By pressing B or X as Sonic or Tails while riding a snowboard you can make them duck. Ducking has no effect on either character and they'll return to normal as soon as they use another animation such as turning or falling.

Similarly, holding down on the analog stick as Sonic will cause him to stand sideways on the board. This seems to be part of a broken braking mechanic, as not only does Sonic attempt to slow down beforehand but neither of these animations appear as Tails - the board just appears to move on its own while playing as him.

The TGS tutorial screens do not mention either of these features.

Tokyo Game Show Leftovers

Within all versions of Sonic Adventure remain the menus from the Tokyo Game Show version of the game. The ID for the current menu can be found at the following address:

  • Japanese: 8C84F4C4
  • US 1.0: 8C822B84
  • US 1.1: 8C81E904
  • Europe: 8C81E844
  • International: 8C8302E4

To access the TGS Menus, change the value to 12 in the Japanese release or 15 in the US, European, and International releases.

NOTE: For emulators the address needs to be adjusted. If using Demul, subtract 60000000. If using NullDC, subtract 6FFE0000.

For the 2004 US PC version, replace the seven bytes at C53A in sonic.exe with seven 90 bytes, or install the "TGS Menus" mod from this page.

Interestingly the address that controls the TGS Menu ID has a value (13) that sends the player to the Chao Garden, but there's no known way of doing this normally.

Title Screen

.neercs eltit epytotorp ehT

The title screen is a simple static image, which for some reason is flipped horizontally. After 10 frames (a third of a second in the Dreamcast version, a sixth of a second in the PC version) it plays Tikal's theme music. After 150 frames (5 seconds in Dreamcast, 2.5 seconds in PC) it displays the unused "Now Loading..." graphic and then plays a demo.

Pressing the X and Y buttons together in the Dreamcast version brings you to the level select described under the "Developer Tools" section, but in the PC version it causes the game to abruptly exit. Pressing the Start button brings you to the character select screen described below.

Pressing A+Start will cause Tails to say "Uh oh, What's this?". Note that if the voice file is swapped with the AutoDemo's, instead the voice that plays will be Knuckles saying (a line that translates to) "How dare you."

Character Select

The character select screen is also rather simple, pressing Left, Right, L, or R will switch the screen between six static images. After 600 frames (20 seconds on Dreamcast, 10 seconds on PC) the game will return to the title screen, although the character select music will continue playing. Pressing the Start button will display the two "How To Play" images and then begin the character's story from the beginning.

Pressing X+Y+A/Start on this menu plays a jingle, but doesn't seem to have any effect otherwise. Holding A or B sends the player to their selected character's demo stage instead of their story, with the B button version enabling controls.

How To Play

How to Play pictures from the TGS version of the game. English versions of these files can be found in the AutoDemo.

Gliding Tutorial

In the TGS version of the game, Knuckles was given a gliding tutorial before playing his stage. While the tutorial doesn't appear in the final game even when accessing the hidden TGS menus, the overlay used for it can still be found in the file K_TUTORIAL.PRS.

Debug Menus

These menus are in the same section of code as the TGS menus, but there does not seem to be any way to activate them other than hacking. Pressing the L and R buttons switches between the three menus and Up and Down changes the current selection within the menu.

The "CHARACTER" menu changes the character you play as.

The "STAGE SELECT" menu allows you to pick a stage to start from, using the same text as the other level select menu. "PRACTICE 1" leads to Hedgehog Hammer, and "PRACTICE 2" and "PRACTICE 3" lead to empty levels. Left and Right can be held to scroll the list faster. In the PC version, the text for the level names was removed, but the "TGS Menus" mod restores the text from the Dreamcast version.

The "ADV SEQUENCE" menu seems to allow you to select a story, but it has no effect on anything.

Pressing the Start button begins gameplay in the specified stage with the specified character. Since none of the proper story events have happened, picking any Adventure Field level will likely leave you stuck with no option but to return to the title screen, and due to an oversight, the game puts you in "Adventure" mode in the Action Stages without setting an Adventure Field to return to, so selecting the "Quit" option from the pause menu simply puts you in Hedgehog Hammer (level 0).

Developer Tools

Level Select

SA LevelSelect.png

In all versions of the game, a level select menu exists. To access it, change the value of the following address to 02:

  • Japanese: 8C7694D0
  • US 1.0: 8C7649F0
  • US 1.1: 8C760970
  • Europe: 8C7608B0
  • International: 8C7622F0

X and B will change your character. The stage list is not visible in the versions of the game with an animated title screen (US 1.1, European, and International), but the character option can still be seen, the cursor can still be moved and stages can be accessed.

Japanese Level List

In each version of the game, there is a Japanese level list in the main executable (pointer table at 1B3EF4 in US Dreamcast 1ST_READ.BIN, 50A250 in US PC sonic.exe), which is not referenced by any code.

 プラクティス 		(Practice)
 エメラルドコースト 	        (Emerald Coast)
 ウィンディバレー   	(Windy Valley)
 トゥインクルパーク  	(Twinkle Park)
 スピードハイウェイ  	(Speed Highway)
 レッドマウンテン    	(Red Mountain)
 スカイデッキ    	        (Sky Deck)
 ロストワールド  	        (Lost World)
 アイスキャップ  		(Icecap)
 カジノ  			(Casino)
 ファイナルエッグ    	(Final Egg)
 きのこ                  (Mushroom)
 ホットシェルター    	(Hot Shelter)
 ジャングル  		(Jungle)
 砂漠    		(Desert)
 カオス0    		(Chaos 0)
 カオス2    		(Chaos 2)
 カオス4    		(Chaos 4)
 カオス6    		(Chaos 6)
 カオスFINAL    	        (Chaos FINAL)
 エッグモービル1    	(Egg Mobile 1)
 エッグモービル2    	(Egg Mobile 2)
 エッグモービル3    	(Egg Mobile 3)
 ZERO    		(ZERO)
 E-101  		(E-101)
 E-101改    	        (E-101 Mk.II)
 シューティング1    	(Shooting 1)
 シューティング2    	(Shooting 2)
 砂ボード			(Sandboard)

Notable items include:

  • Hedgehog Hammer listed as プラクティス (Practice)
  • Three empty level slots listed as きのこ (Mushroom), ジャングル (Jungle), and 砂漠 (Desert)
  • Adventure Fields and Twinkle Circuit listed as empty strings

Collision Display

SonicAdventure CollisionDebug.png

A debug display that shows active collision near the player can be found by changing the value of following address to 0:

  • Japanese: 8C75B740
  • US 1.0: 8C756C5C
  • US 1.1: 8C752BDC
  • Europe: 8C752B1C
  • International: 8C75455C

The display also lists information such as which side of an object the player is colliding with.

SPR Task

A debug feature with 3 displays showing various in-game information. Changing the value of the following address to 1, 2 or 3 switches between displays.

  • Japanese: 8C1D487C
  • US 1.0: 8C1C1D10
  • US 1.1: 8C1BDFD8
  • Europe: 8C1BDF18
  • International: 8C1BE3B8

Free Movement Mode

There is a Free Movement mode that can be used to fly around. It can be found in the Dreamcast version by changing the Action ID to 83 for Sonic, 53 for Knuckles and 49 for Amy. In SADX, these values are 87 for Sonic, 57 for Knuckles and 53 for Amy.

The controls are as follows:
Analog Stick = Move
Analog Stick + X = Move Up/Down
A = Exit Free Movement mode.
B = Go to the current character's start position.

Free Movement mode seems to be partially removed from the game. Big's Free Movement can be seen by setting his action to 55 (59 in Sonic Adventure DX), but the only remaining feature of it being the way his arms move when pressing the buttons to move up or down. Tails and Gamma don't have free movement mode at all.

Leaving Free Movement mode puts the character in an action natural for the current stage. For example, in Icecap and Sand Hill the player will regain their board upon leaving free movement mode. This is the same for stages such as Perfect Chaos, which drops the player as Super Sonic.

Egg Walker

What seems to be a leftover debug feature can be found in the Egg Walker boss fight. Pressing the Y button during the Egg Walker fight seems to cause the Egg Walker to advance to the next cycle of its attack. For example, pressing the button while the boss is stamping its feet on the ground will instantly cause it to walk over to the other side of the arena.

(Source: Sonic Retro)

Error Messages

There are a number of error messages that can appear if the player manages to do things they can't normally do through hacking or other means.

SonicAdventure ActOnly.png

Some objects will only load in certain Acts of Station Square. If the Act ID is somehow changed through cheating, these objects will refuse to load and a message will show up saying "ACT STATION ONLY !".
Likewise, if the player does this in the Casino area it will say "ACT CASINO ONLY !" instead.

SonicAdventure GameBug.png

This error message will appear when the Menu ID is set to 9.

Oddities

Address Directory

In an extremely bizarre event, the root of the JP version's disc houses files labelled PDATA10 through PDATA19. These appear to contain thousands of random Japanese commercial addresses, belonging to various establishments including but not limited to stadiums, hospitals, cemeteries, and even Capcom. Due to their insane length, you can find these on the Notes page along with other minor information.

Developer Text

Upon entering the menu, the following string is loaded into RAM:

Team Andromeda

Team Andromeda was a development team at Sega from 1994 to 1998, whose only known credits include Saturn games. Thus, this could be a remnant from an earlier version of the game.

Limited Edition Advertisement

SonicAdventure LeftoverAd.png

The advertisement for the Sonic Adventure Homepage from Limited Edition is still present in the US, European, and International releases.

The graphics are missing, but the advertisement itself is still fully functional. It can be seen by setting the Menu ID to 12.

Credits

A number of the screenshots used in the game's credits for each story have subtle differences to what's seen in normal gameplay, suggesting that they were created using an older version of the game.

PC Wallpapers

If the game disc is inserted into a PC, a folder can be found containing a selection of different wallpapers depending on which version of the game is being used: