Although "Fallout Shelter" has been considered as a stand-alone title and not as a companion app to the upcoming "Fallout 4" game, many fans still got the game from the iTunes App Store. It even went as far as finishing third top-grossing app on the iTunes App store days after its release. However, the market base for the mobile game is still limited since it is currently only available on Apple devices. 

Developer Bethesda Softworks has assured fans that an Android version of "Fallout Shelter" is already in development. Although no specific date for the release was mentioned, a tweet from the official Bethesda Studios said that the Android version for the title will be coming out in a few months. 

Bethesda announced "Fallout Shelter" as a stand-alone game title for Apple devices on June 15, as part of the developer's Electronic Entertainment Expo participation.

In the game, players need to build and manage "Fallout"-type vaults using a variety of items, weapons, and rewards. Although the title is free-to-play, gamers can opt to buy lunchboxes containing items, rewards, and in-game currency Caps, to level up their vaults faster. Buying lunchboxes is not a requirement, though, and players will not get any penalties if they opt to rely instead on free items popping out when they sent out their dwellers on a search. 

Moreover, there is also no Internet connection required.

During the E3 presentation, Bethesda VP Pete Hines said, "Don't worry, there are no paywall timers, you don't need an Internet connection. You build something, it's instantly built. Again, no Internet connection, you can play anywhere."