esolangs.org/wiki/Y86 mentions:
One specification at: web.cse.ohio-state.edu/~reeves.92/CSE2421sp13/PracticeProblemsY86.pdf
Largest programs ever written:
Machine learning as a form of data compression by 
Ciro Santilli 37 Updated 2025-06-02 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-06-02 +Created 1970-01-01Our Final Invention - Artificial General Intelligence by Sciencephile the AI (2023)
Source. AGI via simulation section.Ciro Santilli defines an "AI game" as:
a game that is used to train AI, in particular one that was designed with this use case in mind, and usually with the intent of achieving AGI, i.e. the game has to somehow represent a digital world with enough analogy to the real world so that the AGI algorithms developed there could also work on the real world
Most games played by AI historically so far as of 2020 have been AI for games designed for humans: Human game used for AI training.
Ciro Santilli took a stab at an AI game: Ciro's 2D reinforcement learning games, but he didn't sink too much/enough into that project.
Bibliography:
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