The White Nightmare game will give you a real test of observation, and there is only one and very simple question: find a white tile. It seems complicated, but as soon as you see the playing field, you will immediately understand why the game is called the White Nightmare. It's a real nightmare, because the tiles are not only small, they are all painted in faded pastel colors, among which it is rather difficult to find a pure white tile. Try to do it as quickly as possible, because the timer is running at the top and it is ticking inexorably. Each wrong click adds a few more seconds to the one already running into White Nightmare.
