Ah, when in-game, press 'Esc' on your keyboard and a menu should open up. Click 'Options', and then another menu should pop up with different tabs and such for you to choose from. Click on 'Video' and on the list that pops up should be 'Fullscreen'. Click that and uncheck the box to turn it off. The same is when on the title screen, just click 'Options', and it should work.~ Hope this helps. c:
