  The Arcade Learning Environment ("ALE") is a widely used library in the
reinforcement learning community that allows easy programmatic interfacing with
Atari 2600 games, via the Stella emulator. We introduce a publicly available
extension to the ALE that extends its support to multiplayer games and game
modes. This interface is additionally integrated with PettingZoo to allow for a
simple Gym-like interface in Python to interact with these games. We
additionally introduce experimental baselines for all environments included.
