Letters from nowhere game

I downloaded the "Letters from nowhere" free game and it won't open. Dragged and dropped it into the trash and downloaded it again with the same results. I have a Mac OS X version 10.7.5 which is later than required. My processor is a 2.4 GHZ Intel Core i5. Memory is 4GB 1333 MHz DDR3. Is my computer not capable of playing this game?

Thanks!!