Everything you need to know about MaoMao Castle is that it stars a flying cat dragon. You are the flying cat dragon, in fact, and you need to chase rainbows and survive without losing your nine lives. That's it. Pretty simple.
Oh but I forgot to mention it speeds up the further you get. What feels at the beginning like a leisurely fly forward in some giant, saccharine pixel world - you wheeling the dragon around carefree with your mouse - soon becomes something else, something like panic.
At the beginning, it's no sweat to fly through the rainbow windows around the course, or cut the grass by swiping side to side on the floor, or collect puzzles, or go over and under walls, or gobble up the pebbles but skirt the lighthouses, or dodge the trees. But as the pace-handle cranks, the objects you're watching become blurrier and blurrier until they're whizzing at you so fast you can't tell what's going on.