Monument Valley
A selection of puzzles from Monument Valley Ustwo

Monument Valley, one of the best mobile games released in the past few years, is currently available to download for free on iPad and iPhone, through Apple's App Store. The award-winning, perspective-warping puzzler was developed by ustwo.

The delightful game tasks gamers with moving players through warped architecture inspired by the paradoxical Penrose Steps and the famous works of artist MC Escher. We ranked it among the very best games of 2014.

We said: "Games are often thought of as lengthy experiences: 60-hour-plus RPGs; moreish online multiplayer shooters; addictive fruit-bearing mobile puzzlers – but sometimes the very best games are short yet perfectly crafted. There's nothing wrong with Monument Valley save its brevity, but that's not a fair criticism, just a testament to developers Ustwo's perfectly pitched puzzle, which presents mind-bending perspective puzzles. A stunning and essential mobile game."

So it's a short game, but now it's free there's no reason to feel short-changed. While you'll work your way through fairly quickly and be left hungry for more, the game is of such high quality that multiple play-throughs are inevitable.

Android users don't need to feel left out. Monument Valley has been free for a while through Amazon Underground.

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