A save game editor for Sonic 3. Written in JavaScript. Sonic 3 and Sonic & Knuckles are platform games released for the Sega Genesis in 1994. The editor works with emulator saves for the original console games as well as with the PC re-releases.
![[Sonic 3 Save Editor]](https://gitlab.com/jcfields/sonic3-save-editor/raw/master/screenshot.png)
There are already editors for the Windows version, Sonic & Knuckles Collection: a JavaScript version written by XFox Prower and a C++ version written by Xeeynamo. The Genesis version is a little trickier: the single-player and competition data are each stored twice for redundancy, with a checksum for each set (for a total of four checksums). If a checksum fails on the first set, the game tries the second set. If the checksum fails on the second set, the game resets the save data to the default values. I isolated the checksum algorithm from the disassembled game and used Easy68k to verify it.
![[Sonic 3 & Knuckles save select]](https://gitlab.com/jcfields/sonic3-save-editor/raw/master/saveselect.png)
The saves directory contains saves in different formats for testing purposes.
| Release | Platform | Year | |
|---|---|---|---|
| ✅ | Sonic 3 and Sonic 3 & Knuckles | Genesis/Mega Drive | 1994 |
| ✅ | Sonic & Knuckles Collection (Sega PC) | Windows | 1997 |
| ✅ | Sega Mega Drive & Genesis Classics (Steam) | Windows, Mac OS, Linux | 2011 |
| ✅ | Sonic 3: Angel Island Revisited | Windows, Mac OS | 2019 |
Tested for Gens, Kega Fusion, and Genesis Plus saves. May or may not work with other emulators since they vary a bit in how they handle saves. The "Show advanced options" checkbox reveals some save options that may help compatibility with other emulators. To save files in this format, select "Console."
Different emulators store saved games in different locations, but they generally have the same name as the ROM file and use the .sav or .srm file extension.
This is the original Sega PC version for Windows 95. It is still playable on modern versions of Windows with Sega PC Reloaded. To save files in this format, select "PC."
The save file is located at [path to game]\sonic3k.bin.
This is the Steam re-release for Windows, Mac OS, and Linux. This version only includes Sonic 3 & Knuckles; data for Sonic 3 is saved but ignored by the game. To save files in this format, select "Steam."
On Windows, the save file is located at %userprofile%\Documents\SEGA Mega Drive Classics\user_[identifier]\Sonic 3 & Knuckles\bs.sav.
On Mac OS and Linux, the save file is located at ~/SEGA Mega Drive Classics/user_[identifier]/Sonic 3 & Knuckles/bs.sav.
Sonic 3: Angel Island Revisited is a fan-made remake of the original game. This version only uses Sonic 3 & Knuckles single-player and competition data; data for Sonic 3 is not saved. To save files in this format, select "AIR."
On Windows, the save file is located at %appdata%\Sonic3AIR\persistentdata.bin.
On Mac OS, the save file is located at ~/Library/Application Support/sonic3air/Sonic3AIR/persistentdata.bin.
Based on the format specification of the PC version by XFox Prower:
Checksum algorithm taken from Sonic Retro's Sonic 3 & Knuckles disassembly by Stealth and contributors.
Uses Classic Sonic icon by Nibroc-Rock and Sonic & Knuckles logo by CatW.
Uses Dosis font by Edgar Tolentino, Pablo Impallari, and Igino Marini and NiseSegaSonic font by Act Select.
- J.C. Fields [email protected]
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