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Sonic the Hedgehog (16-bit)/Miscellaneous Hacking

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SCHG: Sonic the Hedgehog

Level order

Level order in Sonic 1 is stored as a set of values in the following format:

Assume Z is the zone number and A is the act number.

ZZAA

lvl_ord.bin (or Level Order.bin in the HG dissembly) specifies the level to load at the end of each level. Each two bytes are reserved for a different level slot.

So, the format of lvl_ord.bin is as follows, based on the original level order.

GHZ1 GHZ2 GHZ3 GHZ4 LZ1 LZ2 LZ3 LZ4(SBZ3) MZ1 MZ2 MZ3 MZ4 SLZ1 SLZ2 SLZ3 SLZ4 SYZ1 SYZ2 SYZ3 SYZ4 SBZ1 SBZ2 SBZ3(FZ) SBZ4

Say you wanted to USE GHZ4. In that case, assuming an otherwise normal level order, you'd have bytes 05-08 as follows:

00 03 02 00

For those who're not sure of the original zone order, zone IDs are as follows:

ID Level
00 Green Hill
01 Labyrinth
02 Marble
03 Star Light
04 Spring Yard
05 Scrap Brain
06 Ending

Start positions

Same format as the level order- each two bytes are for one act. First is X, second is Y. Easy-peasy.

Level playlists

Each byte represents one Zone according to the original zone order. Simply set it to the ID of the music file to be played.

References


Sonic Community Hacking Guide
General
SonED2 Manual | Subroutine Equivalency List
Game-Specific
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Technical information
Sonic Eraser | Sonic 2 (Nick Arcade prototype) | Sonic CD (prototype; 1992-12-04) | Dr. Robotnik's Mean Bean Machine | Sonic Triple Trouble | Tails Adventures | Sonic Crackers | Sonic 3D: Flickies' Island | Sonic & Knuckles Collection | Sonic R | Sonic Shuffle | Sonic Advance | Sonic Advance 3 | Sonic Battle | Shadow the Hedgehog | Sonic Rush | Sonic Classic Collection | Sonic Free Riders | Sonic Lost World
Legacy Guides
The Nemesis Hacking Guides The Esrael Hacking Guides
ROM: Sonic 1 | Sonic 2 | Sonic 2 Beta | Sonic 3

Savestate: Sonic 1 | Sonic 2 Beta/Final | Sonic 3

Sonic 1 (English / Portuguese) | Sonic 2 Beta (English / Portuguese) | Sonic 2 and Knuckles (English / Portuguese)
Move to Sega Retro
Number Systems (or scrap) | Assembly Hacking Guide | 68000 Instruction Set | 68000 ASM-to-Hex Code Reference | SMPS Music Hacking Guide | Mega Drive technical information