It's creepy and captivating hours. Once started, you can hardly stop. The puzzles are not too difficult, but difficulty adjustable by one the tips or to turn off. The graph I find irresistibly good. It runs smoothly, never crashes. No errors, and also the often small objects you have to find, can be clicked very well. Each screen can be zoomed so that there is no problem to find them. There is simply nothing to complain about. Perfect fun for many hours. Thanks for that!