Hi! Is there an error message that goes with the black screen? If so, it might be a permission issue caused by security measures in your Mac. In that case, just moving the Game.app file to a different location on your machine after extracting it from the .zip file should fix the issue. Alternatively installing the game through the Itch app instead of downloading it manually should also solve it.
Please let us know if this was helpful at all in case others encounter the same issue, and apologies for the inconvenience!