HIII I had this issue too, try this : Open terminal, Type "chmod +x " (Make sure to leave a space after the x and DON'T PRESS ENTER YET), Go to finder and right click the game, Click show package contents, Open contents, Open the file that says MacOS, Find the file that says "TheFalseSun", Then drag that into the terminal, Click enter and try to run the game again.
Should look something like this : 