Interactive fiction has an uphill struggle maintaining a sense of realism. Without the attention-grabbing graphics and sound of twitch titles, it's reliant on words and pictures.

So unless the writing is top-quality, it's hard to shake the sense you're reading an e-book.

Lifeline... has enough top quality writing from Dave Justus, writer on The Wolf Among Us, to avoid that fate. Yet it's chosen to take things a step further.

Rather than just letting the player wander through it at their own pace, Lifeline sets the speed. When the protagonist is sleeping, or busy with a task, you have to wait until he wakes until you can play again.

This sounds like some awful free to play nightmare. "Only $1.99 to wake Taylor early and continue your adventure!" Yet this is a premium app with all the cost upfront.

This sort of approach ought, by rights, to backfire, leaving gamers furious at shelling out for an app they can't play.

But amazingly, it works.

Hook

In retaining control of the pace at which the game unfolds, Lifeline... can do things that other titles can't. It shovels on dramatic tension with a big scoop. It helps maintain a passable sense of realism.

The whole setup for the game aids that sense of things unfolding slowly in real-time. When you start, you're contacted by Taylor, apparently the only survivor of a space ship crash on a distant moon. By some freak of technology, he's managed to open a communications channel to you, and you alone.

He's written as a believable and sympathetic human being. He has definite textual tics and mannerisms that the writer keeps spinning like a tricky set of plates.

At times, he can be pretty irritating. Sometimes he does his own thing, and tells you about it. More often, he asks you for support or advice.

Line

This is where the choices come in. They're always just a binary set of picks. Sometimes it feels as though there's no difference between them, especially when Taylor just wants some words of comfort.

For others though, the difference is very real. The game has multiple endings, many of them tragic. While there's no semblance of strategy here, you need to make sensible choices on Taylor's behalf.

It's amazing just how engrossed this simple, yet incredibly creative, bag of tricks makes you feel. At one point Taylor asked me to go off and research what radiation levels a human could withstand over the course of a night.

And I did. I went on to Google and looked it up, and it wasn't an easy find, either. Just so that I could have an answer for him when he next came calling. Just so I could feel that I'd helped.

To give away any more about the plot would be spoiling things, so we'll leave it there. It's not quite as imaginative as the premise for the game mechanics, but it's good enough. It kept me guessing until quite close to the end.

Sinker

Once you've reached the end, which will take three days, or more if you're not being attentive, what then? Well, you can replay and make different choices. Or even wind back the app to a particular point, take the other branch just to see where that leads.

It's kind of fun finding out where else the story might have gone to, but it's not as fun as the developer seems to think. Once you've played through to the end, the magic is kind of spoiled.

The power to restart or replay the story in chunks removes the sense of realism. You stop caring about Taylor as a person - he's just a tool to help you find new bits of the tale.

So if I was going to criticise the app, it'd be because it's asking a modestly high price for a fairly short play experience. But like other creative apps such as Monument Valley, the content is so unique that it's worth the entry price in spite of of its brevity.

For a few brief hours I cared - really cared - about the fate of a completely fictional character. I don't think any other game I've played has made me feel that way before.