1. Monument Valley
If MC Escher designed a mobile game, this would be it. Guide a little princess through a series of buildings with gravity and physics-defying stairways, doorways, and hallways by altering your perspective on the scene. It's gorgeous, beautifully scored, and racking up awards, like the 2014 iPad Game of the Year, and a 2015 BAFTA, to name a few. $3.99, available for iOS and Android.