I wasn't sure I'd like this kind of nanogram because so many reviews said it was very challenging and I like easy, friendly, relaxing games like the Penguins. Purchased Wolf's Stories first and got totally hooked so I was very happy to find this one also by New Bridge Games. This game does require a lot of concentration, logic, focus. I find that it helps me leave the work day behind because I put all of my mental effort into this game. Top tip: use the hints, you aren't penalized for it. And remember to switch your color...the game won't do that for you and there isn't an "undo."