Unfortunately the xbox one controller still isn't working properly in the latest demo: 'A' button doesn't work, so I cannot even get past the first logo. Btw it seems that the keyboard controls are disabled when a pad is connected. I tried disconnecting the joypad and I could get past the logo. If I then plug-in the Xbox controller, I can see that only a few buttons seem to do something: moving the left stick to the right makes the player go down. And that's it. Other keys don't seem to work properly.
Has the Xbox support been tested on macOS (Mojave)? I can do more testing if you need it.