Sonic 4 Ep. II Recomp
Reverse engineering Sonic the Hedgehog 4: Episode II's engine data
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
- Byte-level reverse engineering of the engine's data files, with the format documentation written as the formats are decoded.
- Python tools that extract and inspect the real game data, so every documented field is verified against actual files rather than assumed.
Outcome
Freshly started and public: format documentation and a growing toolset over the AliceNN engine's data files, building toward the re-implementation.
Built with
- Python
- Reverse engineering
- File formats