A Series of Random Events
Fallout shelter is a management sim in the of style of XCOM: Enemy Unknown's base development. You'll have to nurture and oversee the growth of your vault and the dwellers within, reacting to their every need. Vault dwellers can be assigned to different themed rooms such as med bays, power rooms and water treatment rooms created by spending caps earned by levelling dwellers, selling goods and other such activities. You can earn caps to spend on new development, assign dwellers gear, and send dwellers into the wasteland to gather supplies (though they take millennia to reappear). You'll put in a lot of effort trying to make your vault and its dwellers as strong as possible whilst fighting against the games own restrictions of timed events which require you to literally wait I real time so you can come back later when the game is ready for you to continue, fighting against the fact that lunch boxes carrying random supplies can be purchased with real money, nullifying the hash game economy, and fighting against the fact that everything you do is left up to chance.
It will all be for nothing in the end. The investment in your personal, persistent development which is so crucial to these types of mobile game's success will be for nothing when the game just decides “Fuck everything that you've been doing, forget the countless hours you thought you had spent carefully pondering over whom to send out on missions and where to assign dwellers because we're going to assault your base with a bunch of raiders that you had no idea would come and have no defence against whatsoever!” Great game design, that. The illusion that so many games of its ilk successfully sustain is instantaneously, broken. It's all random in the end, it's all pointless. A treadmill leading nowhere that can be turned off at the games whimsy.
It's not entirely without merit. It certainly succeeds in capturing that fallout feel but sharp, colourful assets and a nice tilt effect for mobile devices can't hide a shallow management sim with no to little skill involvement. A shame. This marketing tool had the potential to be something really interesting. The concept, the theme and the management genre all fit together tantalisingly well which is why it's such a disappointment that despite Bethesda's freedom to work on Fallout Shelter as something extra in addition to Fallout 4, it fails to distinguish itself from the hordes of free to play, micro-transaction driven bilge begging for your money. The mobile game market's trappings and Bethesda's taste for money impede this idea from working.
It is admirable that the game really does let you fail unlike similar mobile games that give you consistent progress with the illusion of skill, but the solution certainly isn't to make so many irritating to playthrough ending-ly disastrous random events that you end up feeling completely powerless. When the novelty of the Fallout aesthetic wears off, it's a chore.