Itch.io version is no longer being updated. Steam version is currently Windows only but devs have said they will look into supporting other platforms (MacOS, Linux, Consoles) once the Windows version is completed. For now though their focus is completing the game on Windows first.
The Devs seem lazy for as much money as they're making. Not to worry the Nvidia Geforce Pro runs the game from your steam account its not laggy and works great on my MacBook Pro. It's allowed me to play 5 PC only games on MacBook.