I wouldn't be too sure about that. The original decompilations of Mario 64 and Ocarina of Time were done mostly by hand because LLMs weren't really around yet, but these kinds of projects seem perfectly suited for handing the gritty work off to AI: There is a clear output (exact binary recreation) and a straightforward path to get there (look at this assembly code and produce some C code from it). The decompilation of Twilight Princess jumped from very little to basically 100% of core code in the past year alone: https://github.com/zeldaret/tp

I have no doubt that this would be possible for MGS2 as well.

Absolutely. This is just some delusions of a vibe coder at best. Not with just current generation of AI tools but essentially never. The conversion from C, C++, Rust or whatever, through post-processing (macros etc), through IR generation, through compile time optimizations, through link time optimizations, to the generated machine code is a one way street for low level languages. You can get a pretty close higher level approximation that matches the flow/logic/structure - but the code will never be anywhere near close to the original source code. I could write the same C++ program in 3 different ways and get identical assembly, how do you go back to the exact source? The answer is that you don't.

Here's the same simple program, written in 3 different ways, producing identical binary compatible code: https://godbolt.org/z/qWrc8fEnn

How does the AI know whether it should produce back the snippet #1, #2 or #3? It does not. It cannot.

That's pre-2026 thinking. At this point, with the ability to lash IDA or similar tools to an agentic harness, there is no longer any such thing as a closed-source binary.