This repository contains the fully decompiled source code for the PlayStation 2 game 'Shadow of the Colossus' (codenamed Veronica), paired with the complete custom toolchain required to rebuild it from source. It is a landmark project in game preservation and reverse engineering, providing a fully functional build environment that outputs a bootable PS2 disc image. The architecture is a monolith of game logic, middleware, and system libraries, orchestrated by a sophisticated Python-based build system. The repository is structured into several key domains: the game's C source code (src/ps2/veronica/prog/), which includes the engine, gameplay logic, and hardware abstraction layers; the CRI ADX audio middleware (src/cri/); and the cross-compilers for the PS2's dual processors, the Emotion Engine (EE) and I/O Processor (IOP) (compiler/). The build process is managed by compile.py, which reads game-specific configuration from the config/ directory to handle different retail versions (e.g., SLPM_650.22 for Japan, SLUS_201.84 for North America). The primary data flow involves compiling the C source with the ancient GCC 2.x cross-compilers, linking against the provided libraries, and assembling the final ISO with mkiso.py. The project demonstrates exceptional craftsmanship in embedded systems reverse engineering, particularly in the decompilation of the CRI middleware and the recreation of the PS2 system library stubs. While the toolchain is inherently tied to a legacy platform and the code is decompiled (lacking original developer intent), the build system and organizational patterns are a valuable reference for any similar decompilation or homebrew project. The codebase is effectively frozen in time with its target platform, representing a high degree of technical drift from modern software ecosystems but perfect alignment with its preservation goals.