Did you download the .asav file from here and drag it into the game window (or click the import game option to choose the file)? You can try sending me a link to the asav file and I can see if it's a problem with the file.
You can actually already download the demo for mac on itch: https://fancyfishgames.itch.io/aground . The full version will continue to have mac builds.
 "Aground"){kind=icon}
 "The Awakening RPG"){kind=icon}
 "Supermechs"){kind=icon}
 "Swords and Souls"){kind=icon}
 "Idle Raiders"){kind=icon}
 "Time Clickers"){kind=icon}
 "Death Squad"){kind=icon}
 "Dream Car Racing Evo"){kind=icon}
 "Galactic Clicker"){kind=icon}
 "Mine Blocks"){kind=icon}
 "Epic Creature Hunter I"){kind=icon}
 "Anti-Idle: The Game"){kind=icon}
Did you download the .asav file from here and drag it into the game window (or click the import game option to choose the file)? You can try sending me a link to the asav file and I can see if it's a problem with the file.