This must-play iPhone game puts an astronaut's fate in your hands - and it's free this week

Over the long holiday weekend, I started playing "Lifeline," an iPhone game that puts you in control of the destiny of a shipwrecked astronaut named Taylor marooned on a distant planet.

If you want to play "Lifeline," and you absolutely should, you're in luck - it's Apple's free app of the week on the App Store. The Android version will run you $0.99.

The setup to "Lifeline:" After Taylor's science vessel crashes in a freak accident, he or she - "Lifelife" never specifies Taylor's gender - calls for help. And through whatever fluke of fate, Taylor's communication system finds your iPhone.

From there, gameplay takes the familiar form of text messaging. Taylor keeps you posted on what they're doing as they explore the planet, salvage what they can, scavenge for food, and look for a way home.

So, no, it's not the most graphically-intensive game, given that it all plays out over text. But if you have at least a little imagination, and some patience for a game that goes at its own pace, and the willingness to make hard choices, it's well worth playing.

On the regular, Taylor will pose a question to you asking what they should do next - look for food or investigate that strange noise? Push on towards that strange-looking mountain in the distance or find shelter for the night?

And to answer the question you're thinking, yes, it has more than a little in common with smash-hit book/movie phenomenon "The Martian."

There's a real tension to "Lifeline." It plays out more-or-less in real time. If you tell Taylor to get a move on and march to shelter, it might be an hour or three in real time before you hear back.

It also means that if you make a difficult choice, you don't get to find out if it was the right call until Taylor gets back to you. I ended up more than a little anxious every time Taylor made camp, afraid that somehow one of my decisions had led to their demise.

At least once, that did indeed happen. But the game lets you rewind to key parts of the story and make new choices without having to start all over, which is nice.