Monument Valley is a fine game. "Fine" as not in a week form of "good" but as in indicating exquisite craftsmanship. Something you'd say about a watch or a piece of jewelry.
It features little Ida, the protagonist, who must overcome obstacles and help the lost people of a mythical monument valley. The valley itself is pure visual poetry. An Arabian Nights meets the Miyazaki sensibility of beauty and perception. The problems presented in visual splendor can only be solved if you are willing to relax your hard sense of geometry and laws of physical structures thereof.
The graphics are stunning. Sometimes you just want to look at them and let them soak in. However, what really makes this game stand out is how relaxed and almost laid back the gameplay is. How fast you go is really up to you. Going fast gets you nowhere soon. In fact, the whole idea seems to be to engage more than to escape - which is a novelty in the brief gaming style popular on phones and tablets.
It is a bit brief - featuring 10 levels. So you will probably be done with it in a few hours - or weeks - depending on how you approach it. It took me a few hours spread over a couple weeks. My 7-year old, on the other hand, wrapped this up in less than a week with just a little help here and there. I was amazed how fast she got through it. Probably because kids have imaginations that aren't restricted by preconceived notions and hard facts about geometry.