The approach builds on decades of console emulation, which emerged in the 1990s in the 2D era and gradually extended to 3D machines such as the PlayStation 1 and Nintendo 64, and by the early 2020s even covered the PlayStation 3 and its notoriously awkward Cell processor. What remained was the dedicated development time: analysing a game's executable, the files it reads, its system calls and memory allocation, where one errant byte is a bug. That repetitive, exacting work suits computers well, and 2026's AI models follow complicated instructions closely enough to work with a high degree of autonomy, while cheaper variants keep token costs manageable on a huge project.

Hallucinations, the usual hazard of AI-generated code, are kept in line by verification: the agent hands over decompiled source code, which is recompiled and checked against the original byte for byte. If the output is wrong, the agent can simply try again until it matches. The bills can still be steep, though. The Modern Warfare 2 decompilation reportedly took three months and up to 700 billion tokens, and its developer might have saved both time and tokens had REA been available.