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SCHG

Sonic Chaos/sandbox

From Sonic Retro

Credit goes to Hivebrain for the SMS notes, Ravenfreak for the GG notes, and nineko for the music hacking notes.

Note: Most compressed art and some uncompressed art is located at the same offsets in the GG version.

Master System ROM contents

Offset Description
$8D8-$AD0 ASCII - Level Select
$AF6-$C28 ASCII - Sound Test
$10000 Uncompressed art - Sonic (Same in GG)
$13D00 Blank
$14000 More uncompressed Sonic art (Same in GG)
$16940 Uncompressed art- Tails (Same in GG)
$17680 Uncompressed Art - MGHZ Pole Climber Boss (Same in GG)
$17EA0 Blank
$18000 Uncompressed art - More tails
$1BC80 Blank
$1C000 Uncompressed art- More Sonic
$1FA40 Compressed Art - HUD & Numbers (excluding icons)
$1FC6E Blank
$20000 Uncompressed Art - Even More Tails
$23340 Compressed Art - Icons, Spikes, 16x16 blocks, HUD & Numbers (this stuff gets overwritten in vram)
$23B92-$24000 Blank
$24440 Uncompressed Art - Signpost (124 tiles)
$253C0 Compressed Art - cone enemy (SEZ)
$255A0 Compressed Art - flying enemy - facing right (THZ, GPZ, EEZ)
$25690 Compressed Art - flying enemy - facing left (THZ, GPZ, EEZ)
$25780 Compressed Art - beetle enemy (GPZ)
$25950 Compressed Art - spring enemy (SEZ)
$25AB0 Compressed Art - Motobug (THZ)
$25CD0 Compressed Art - Spring Enemy (MGHZ)
$25EE0 Compressed Art - coconut bomb (MGHZ)
$26030 Compressed Art - spring
$261C0 Compressed Art - THZ Platform
$262C0 Compressed Art - GPZ Platform
$26370 Compressed Art - SEZ Platform
$26470 Compressed Art - MGHZ Platform
$26570 Compressed Art - APZ Platform
$26630 Compressed Art - EEZ Platform
$26720 Compressed Art - Shooting Star (GPZ)
$26780 Compressed Art - oil splash (MGHZ)
$26840 Compressed Art - Pogo Spring
$26A50 Compressed Art - Bomb enemy (EEZ)
$26B60 Compressed Art - Water Surface Wave
$26D20 Compressed Art - Laser Canons (EEZ)
$26F10 Compressed Art - Oil Splash (duplicate, MGHZ)
$26FD0 Compressed Art - Unknown/unused (EEZ)
$26FF0 Compressed Art - Sliding Cart (EEZ)
$27090 Compressed Art - Harpoon (APZ)
$27150 Compressed Art - Penguin enemy (APZ)
$272C0 Compressed Art - Bubbles (APZ)
$273E0 Compressed Art - Spring (final frame?)
$274A0 Compressed Art - Splash (APZ)
$27600 Compressed Art - Robotnik (Intro)
$27B60 Compressed Art - Tails (Intro)
$27D90 Compressed Art - Sparkles (Good Ending)
$27EC0 Uncompressed Art - "TM" (4 tiles)
$27F40 Blank
$28000 Uncompressed Art - Tails (75 tiles, includes looking up, flying, and inside cart from EEZ)
$28940 Uncompressed Art - THZ Motobug Boss (72 tiles)
$29280 Uncompressed Art - GPZ Caterpillar Boss
$29F80 Uncompressed Art - SEZ Spring Boss
$2A840 Uncompressed Art - APZ Pod Boss
$2B8C0 Blank
$2C000 Uncompressed Art - Final Boss
$2FE40 Blank
$2FD00 Uncompressed Art - Smoke Puff from Enemy/Monitor
$30000-$33FFF Blank
$354BC Uncompressed Art - Signpost (Final Frame)

A note on the loop motion data. Loop motion data is split up into four parts in Sonic Chaos. 2 arrays handle the camera, 2 handle player movement. The full array for when the player goes through the loop forwards is located from $34000-$346AD. The array for when the player goes forwards through a loop is located at $346B0. Camera movement for when the player goes through the loop backwards is located at $34A48. Like in Sonic 2 (8-bit) you can change this to anything, keep in mind to have it look right you need to edit not only the player movement data, but the camera movement as well.

Game Gear ROM contents

Offset Description
$1F7C0 HUD Numbers and Km/H compressed art
$1FD80 Uncompressed art - Tails (430 tiles)
$40A70 Intro/THZ Tiles
$41F4A GPZ Tiles
$5FF00 Sonic Tripping (Uncompressed, 66 tiles)
$6A8B7-$6AAB6 ASCII Credits text
$74580 Uncompressed Art - Rings (16 tiles)
$74780 Uncompressed Art - Unknown (GPZ Stars?)

Music editing

Song
ID
Location in the
Master System 1.2 version
Location in the
Game Gear 1.0 version
Usage in the
Master System 1.2 version
Usage in the
Game Gear 1.0 version
81 9169 91B7 MS Turquoise Hill GG Turquoise Hill
82 963F 975F Character Select Character Select
83 9793 985D MS Gigalopolis MS Gigalopolis
84 9CE8 9DB2 Invincibility Invincibility
85 9EB2 9F7C Rocket Shoes Rocket Shoes
86 9F7A A044 Unknown Unknown
87 A005 A0CF Game Over Game Over
88 A0A5 A16F Stage Start Stage Start
89 A152 A21C Stage Completed Stage Completed
8A A1E1 A2AB Chaos Emerald Chaos Emerald
8B A23D A307 Final Boss Final Boss
8C A948 AA12 Boss Boss
8D AF69 B033 Good Ending Good Ending
8E B634 B6FE Unused Unused
8F B6C4 B78E Special Stage Special Stage
90 B8EB B9B5 MS Intro GG Electric Egg Act 3
91 BEF6 BFC0 Sleeping Egg Sleeping Egg
92 C3DD C4B4 Mecha Green Hill Mecha Green Hill
93 C8B6 C98D MS Aqua Planet GG Aqua Planet
94 CFDD D0F9 Continue Continue
95 D206 D322 Electric Egg Electric Egg
96 D7DC D8F6 Death Death
97 D881 D99B Boss Defeated Boss Defeated
98 D91C DA36 Try Again Try Again
99 D991 DAAB Title Screen Title Screen
9A DBCA DCE4 Bad Ending Bad Ending
9B DE54 DF6E Blank Sunset Park 3
9C DE6E E52D Blank GG Gigalopolis
9D DE88 EBCC Blank GG Intro
9E DEA2 ECF4 Blank GG Special Stage
9F DEBC F16F Blank Speed-Up Shoes

RAM editing

While most of the RAM addresses are the same from S2 SMS, some are different. Listed bellow is one that's not in S2.

Offset Description
$D3A1 Flying Counter, this is set to 300 and counts down to zero. Determines how long Tails can fly. Setting

this to a different value can make him fly constantly until he colides with objects and or the floor.