If you run the game on a standalone mac using only the mousepad, what options (if any) are there on "joysticks"? Can one use keyboard instead?
Modern Macs are supported. See https://itch.io/t/2905056/system-requirements for more info.
Currently it's possible for one player to use the keyboard while another player uses the mouse. The mouse control only uses the primary button, so it's possible to use a touchpad, but for me personally I'd probably mess up a lot if I tried, although there are some systems in place which helps prevent an accidental button press with a mouse that would result in letting a MULE go free.
Joystick / gamepads are also supported.