The creators of Fallout 4 have released a new mobile game associated with the Fallout franchise. In Fallout Shelter, you make your own nuclear shelter, or vault. As the overseer of said vault, you will then need to maintain the underground base, keeping your residents happy.

The game has a 2D-animation look playing off the Pip-Boy characters of the Fallout series. The game looks like a cross between SimTower and the base management system in XCOM: Enemy Unknown.

Residents are able to perform various activities, and reproduce to make new residents. Parts of the shelter serve various purposes meant to help the underground community grow.

The game is free on iOS tonight. It won't have paywall timers and won't require an internet connection to play.

Correction, 11:30 p.m. An earlier version of this post incorrectly reported the game would be available on Android as well as iOS.