It plays out in real time, notifying you via your phone's alerts, through which you can also respond to and interact with Taylor, making this the first mobile game that I know of that can be played via the lock screen. The mechanics are what set Lifeline apart. The troubling part is that none of the decisions are good ones and one wrong move could land Taylor in serious trouble. As Taylor sets about exploring the inhospitable environment, you'll help make decisions on what to do next. Reaching out on comms, Taylor is able to find a single person, a single lifeline.
Taylor is the sole survivor of the crash of the Varia, on a barren moon somewhere in the vicinity of Tau Ceti. and your decisions could get the protagonist killed. Lifeline is a text adventure, but one with a serious difference and much higher stakes than you might be used to.