Monument Valley is one of the most frustrating games I have ever played.
Not frustrating because it is particularly bad or because it is hard, but because there is potential here for something truly spectacular, but the game never embraces it. It's a puzzle game without puzzles. It plays like an adventure game, but there's no adventure here either. Playing the game feels like watching someone show you slides of their concept art while music plays in the background. It's pretty to look at, but tedious and boring to actually play.