You are trapped in a mine. You have to dig in the gems to be able to get out, because if not the level will go up and you will die. To dig you have to press 'Enter' plus the direction that you want to dig in. To move around the screen use the cursor keys. If you want to use the digger that appear on some occasions you will have to press 'Shift' + the direction. If you dig a bomb two rows of gems will disappear.