Fallout Shelter is a game that can be played on both desktop and mobile. It is rooted in the Fallout series, and debuted in 2015 as a free-to-play experience. Initially perceived somewhat as a quirky marketing ploy, it leaned towards being a promotional tool rather than a comprehensive game. However, the game has now evolved into an excellent, fun-to-play colony-building game, with live service aspects such as a cash shop.