This repository is a bit-exact decompilation of Touhou Koumakyou ~ the Embodiment of Scarlet Devil (TH06) for Windows, aiming to reconstruct the original executable from scratch using reverse engineering. It is primarily an application—a full game reimplementation with subsystems for graphics (Direct3D8), audio (DirectSound, MIDI), input (DirectInput), enemy scripting (ECL), sprite animations (ANM), replay recording, menu UI, and more. The build system uses MSVC 7.0 and DirectX 8.0 SDK, orchestrated by Python scripts and Ghidra for analysis and comparison. While the core purpose is binary-matching reconstruction, the project also functions as a research repository for understanding the game's internals, with extensive mapping data (CSV files) and Ghidra export scripts. The codebase is large, tightly coupled via global singletons, but contains several self-contained reusable components such as the Chain callback system, PBG3 archive parser, DirectSound wrapper, MIDI player, and a standalone PE file parser (pefile.py). Active development and CI indicate ongoing work to complete the decompilation.