On some Macs, when the game is in full screen mode, the onscreen graphical interface elements don't correctly align with the clickable hotspots that the mouse can interact with. They're not far off from where they're supposed to be, but they're off enough to make you think the game is completely unresponsive. Once the game is in Windowed mode, the elements all align up again, and the game is perfectly functional.
To get the game out of full screen, you'll need to get a feel for where the clickable places are. You'll mouse around the button or box you're wanting to click, you should see the mouse pointer change or flicker slightly to indicate that you're over the clickable spot. Once you find where in relation to the graphic the clickable hotspot is, the rest of the clickable elements will be similarly displaced from their graphics and you can use that to click the elements that you need. You want to navigate your way into the game options, and uncheck the fullscreen box, and then click on the save button.