Five minutes into XCOM: Enemy Unknown, and already three of your four troopers are dead. They've been out-flanked, out-gunned, and outmatched. The first chap was blasted by the soldier we were supposed to be rescuing; he'd been possessed by one of the Sectoids - a classic alien grey, hiding in the shadows. The other two, well... they were the victims of bad orders.

But here's the thing: we were forced to give the poor suckers those commands, because this is the game's tutorial. And with hindsight, it becomes clear that their deaths were supposed to be teaching us something: In this game, poor tactics are rewarded with fatal failure.

It's an encouraging sign for anyone afraid that Firaxis' reboot of Microprose's strategy classic was going to give us an easy ride. Even over the brief course of two early missions, it's clear that reckless play will lead to dead XCOM operatives; given the new emphasis on developing and levelling your squaddies, that's really not something you want to happen.

There's a palpable sense of danger to XCOM's missions, which is exactly as the game should be. You edge out into the unknown, spreading out your vulnerable quartet so as to cover as many angles as possible. Even with the inherent benefits of turn-based play, it's still easy to panic when enemy contact finally takes place. Sure, you can take all the time you want with your decision-making, but making the wrong call will probably lead to disaster.

In the heat of the moment it's easy to make tactical blunders, too. Your squad might encounter a Thin Man, for example - a spindly new foe created by Firaxis. You command one of your guys to rush in, closing the distance to maximise the chance of a successful hit, and then you let rip. But you've forgotten that when a Thin Man dies, he lets off poisonous gas: you trooper blows away his target, and suddenly he disappears beneath a cloud of purple toxin.

The control system here is a lot simpler than the one found in 1994 original. Broadly speaking, each turn allows you to give your troopers two commands. You can either move and then act (shoot at an enemy, duck into cover), or you can spend both commands on a single extended dash; while performing one of these mad sprints you're slightly harder for the enemy to hit, so they're quite useful for getting your chaps into more useful positions.

From the looks of things, positioning is key. Later stages of the game open up toys like grappling hooks and flying suits, but even in the early assaults there's a lot to consider: directional cover, elevated lines of sight, and the seemingly endless number of places that could be housing a threat. With the reduced headcount and streamlined command setup, missions progress at a far quicker rate than the original, but the overall tactics feel very similar - and when, at the end of your turn, the game announces the unseen movement of your alien foes, there's a familiar spike in tension. Clearly, this is A Good Thing.

Given the relative brevity of 2K's latest demo, it's harder to make much assessment about the management side of the game. The so-called Ant Farm view of your base is certainly a wonderful touch, allowing you to zoom in to inspect tiny details as your people go about their business. It's also neat that your science and engineering divisions are headed up by NPCs who announce the latest discoveries and research options. We've seen this sort of characterisation from Firaxis before, though it's also quite reminiscent of the campaign mode in StarCraft II.

The developers clearly want XCOM to be a narrative experience, but hopefully each player's story will be born out of the way they choose to play and their good or bad fortune, rather than from a glut of fixed cutscenes. Beyond an animated intro and a comically brief ending sequence, the original game lacked much in the way of scripted plot - and yet everyone who played it could cite dozens of shaggy dog tales, this being just one of the reasons why it's such a well-loved property.

Will this new XCOM produce its own set of war stories? We can only cross our fingers at this point, but on current evidence Firaxis is certainly on the right track.

XCOM: Enemy Unknown is due for release on PC, Xbox 360 and PlayStation 3 this autumn.