The Arcade Learning Environment

Arcade Learning Environment (ALE) is a widely used open-source framework that wraps hundreds of Atari 2600 games via an emulator and presents them as RL environments for AI agents. It decouples the game/emulation aspects from the agent interface, providing a clean API (C++, Python, Gymnasium) so researchers can focus on agent design rather than game plumbing. This environment suite has been central to many RL breakthroughs, including value-based agents, deep Q-nets, and general-agent benchmarking, because the Atari games span many genres and present diverse learning challenges (pixels, actions, delayed rewards). The repository supports multi‐platform build (Linux, macOS, Windows), vectorized execution of games, Python bindings, Gymnasium registration, and a large set of game ROMs bundled for convenience. While its rendering may not match modern 3D environments, its importance lies in reproducibility, benchmarking, and the fact that many RL baselines and papers reference ALE.