We've updated the Mac & Windows versions of Moon to use SteamInput, which will allow you to automatically use a controller with the game!
If your controller isn't automatically recognized, please refer to the link that corresponds to the controller you are using:
PS4 Controllers (DualShock 4)
steam://controllerconfig/1714580/2738724295
Xbox One Controllers
steam://controllerconfig/1714580/2738932238
Nintendo Switch Pro Controllers
steam://controllerconfig/1714580/2739850974
If you experience any issues after the update, please let us know via the forum.