Sonic 4: Episode II Research
Mapping undocumented binary formats until the work is checkable
Engineering research · Jul 2026 – present
The problem
The AliceNN engine stores its assets in undocumented formats nothing public can read. A portable re-implementation cannot begin until the containers, meshes and textures are mapped byte by byte, and documented well enough that the work is checkable.
Approach
- Decode structures byte by byte against lawfully obtained local inputs.
- Document fields alongside the tools that consume them.
- Keep public verification independent of copyrighted source assets.
Outcome
A clean clone passed 325 C# tests, 15 Python tests, and an Android Release build; complete engine and game compatibility are not claimed.
Built with
- C#
- MonoGame
- Android
- Python
- Binary formats