Deep down, we all like to think that if disaster strikes, someone would be around to help us. Maybe that’s the scariest thing about upcoming survival game I Am Alive: how very alone your character seems.

We felt that strong sense of isolation throughout a recent demo of the game, which has been significantly refocused since its 2008 unveiling and is now headed for Live Arcade instead of retail shelves, says publisher/developer Ubisoft. As I Am Alive opens, it’s one year after some unexplained cataclysm, known simply as The Event. It’s taken your unnamed character that whole time to reach his fictional hometown of Haventon, where he hopes to find clues to his wife and daughter’s whereabouts.

Between the game’s stark visuals (everything seems filtered through layers of white, grey, and sepia) and the collapsed bridge on the city’s outskirts, the situation looks dire. But to reach your old apartment, you must get across, so you clamber up a column and begin making your way along what’s left of the structure. Welcome to your first dose of mortality: a stamina bar. Heavy exertion — scaling ladders, shimmying along ledges — makes the bar rise ever-closer to a red “fatigue” zone; reach that point while climbing, and you’ll need to hammer the right trigger to make an extreme effort (say, a last-second leap to a ledge above) that keeps you from falling to your death.

You can recover stamina by resting or using various collectibles (canned fruit, adrenaline syringe), but either way, you’re reminded of your limits as an action-adventure character. You’re just a normal guy, and the toxic dust lingering in some streets will deplete your stamina until you are dead. So you’ll have to be smart in these polluted areas: moving quickly to reach the ground above them while risking brief time in the dust to pick up, say, a precious piton, which you can use to stop and rest in the middle of a long climb.

Navigating the devastated city seems captivating in its own right — and creepy, too, as you pass wrecked cars and hear occasional cries for help in the distance. But the other, bleaker side of I Am Alive is your interactions with other survivors. Our demo included a couple of these encounters, and one sequence in particular oozed the kind of post-apocalyptic dread you’d find in genre classics like The Road or Book of Eli. Down in a subway station, our character came upon a four-man gang that quickly surrounded him, with one member leering: “Bend over, kid. You ass belongs to us now.” Pondering the fact that our gun had only a few bullets, we noticed an on-screen prompt that appeared when we shuffled close enough to a gang member. Hit X in this scenario, and you’ll do a surprise kill — which in this case, involved our slashing the thug’s throat with a machete before anyone could react. We then pulled out our gun and shot another enemy, who happened to be the leader.

Now our hero had only one bullet left, but thankfully, the two remaining thugs cowed in submission, terrified by their comrades’ fate. Saving his ammo, our demo guide pistol-whipped them into unconsciousness, then kept moving. Not everyone you meet is evil, it seems: he stumbled by two men who offered some of the rat meat they were grilling up. Naturally, he took it (good for the stamina, y’know) and kept walking…only to run into another gang that was eating people, according to a prisoner who begged for his release. After another vicious fight, we heard quiet sobbing and realized something we’d somehow missed: in this entire underground segment, the protagonist had been carrying a young girl on his back, Mei. Knowing only that she’s been orphaned by the undisclosed disaster, we were intrigued by the protective relationship her presence opens up, even if, as we're guessing, she’s with you for only a short while.

Humanity, like ammo, seems scarce in this post-apocalyptic world. We were a bit startled, in fact, by I Am Alive’s unrelenting grittiness — but not in a bad way. If anything, that darkness should up the ante on everything you do. The source of disaster isn’t important, we’re told: though the game will drop hints about what happened, it’s not explained per se, despite several characters posing theories about it. What matters in I Am Alive is surviving, pure and simple. And hopefully, reuniting with your family. Put in that situation, wouldn’t we all fight for that?

PUBLISHER: Ubisoft  •  DEVELOPER: Ubisoft Shanghai  •  MULTIPLAYER: No  •  RELEASE DATE: 2012  •  FOR FANS OF: The Road Warrior, bottled water