You've probably already heard of Monument Valley but it bears repeating. This game is beautiful; like an interactive painting. Y'know when you're walking around and you try to line up the edges of buildings—Monument Valley is that in gorgeous game form.
The only criticism I have is that it's a little short, but the optimist in me sees that as a compliment. This game is so well-done, I just never want it to stop.
It's unfortunately catching a lot of shit because of the amount it costs for the amount of content and this is such a bugbear for me with the current state of mobile gaming. For £4, Monument Valley gives you a couple of hours unique gameplay, and I've replayed the original game twice after completing it just because it's such a nice thing to look at. I will definitely replay the DLC.
I realise I might be in the minority because I do spend a lot on games, but my lunch cost £4.50 today and it has no replay value at all. If you appreciate good design of any kind, you'll appreciate what has gone into creating Monument Valley.