Mere words cannot adequately describe how shocked, confused and disappointed the gaming community became when 2K Marin announced that they were interpreting the venerable X-COM franchise as a linear first person shooter with investigation and survival horror elements. What were they thinking? How could they get it so utterly and completely wrong? Why, 2K? Why?! The pre-E3 trailer did little to clear up the situation, instead intoducing some brightly-lit cover combat sections that seemed at odds with the moody visual style they were shooting for. With the burning need to know more throbbing at the front of my mind, I sat down in their lavishly-appointed demo theatre... where 2K Marin wasted no time in admitting that they'd made a huge mistake.

X-COM isn't about tight scripting and gunplay, they explained. The series hinged upon high strategy and non-linear decision making, and after stepping back and looking at the project objectively, they realised that they'd have to go back to the drawing board in order to do it justice. The first person perspective has remained, but now the action takes a back seat to clever tactical play and the ability to fight the campaign against the otherworldly Outsiders on your terms.

My cynicism and suspicion soon turned into cautious optimism and excitement after watching the demo, and I'll attempt to explain exactly why.

The demo started out in XCOM's secret base of operations, where the secret government team meets between missions to choose strategy, research new hardware and decide how to best combat the insidious alien menace that threatens the very fabric of 1960s American society. Players assume the role of Special Agent William Carter, and talking to NPCs around the installation activates accessible menus for designating research objectives, managing squad members, tweaking loadouts and recruiting new operatives. This is all well and good, but successfully accomplishing these goals will require a huge amount of resources as well as raw alien tech to study and subvert. This is where the new non-linear focus makes its first, and very welcome, appearance.

The base is dominated by a bustling operations centre, containing an enormous map screen that allows players to choose from a wide and varied selection of subquests as well as main mission objectives. These optional jaunts are time-sensitive, and revolve around collecting raw resources to power the war effort, meeting and enlisting new squaddies or acquiring advanced enemy technology ahead of time in order to bolster weapon research. Managing your time properly and deciding on a course of action will dictate the tactical options available to you in combat, and though it may seem attractive to blast through the story missions, taking on the extra work will pay dividends in the long run. It's currently unclear whether taking on these subquests will influence the story as well as the gameplay, but 2K are set to make a few announcements on the subject over the coming months.

Time was short, however, and 2K was keen to push on with the main story objective. Players will be able to take two team members into each mission, each of whom gains experience and skill points from previous sorties to invest in a selection of streamlined upgrades. After choosing a powerful shield and a diversionary light show for our two cohorts, it was time to take to the tilt-rotor Sky Ranger and investigate an abandoned military checkpoint in search of an influential scientist.

After getting boots on the ground and cautiously searching through the suspiciously silent checkpoint, our intrepid guide made first contact with an infiltrator alien disguised as a human soldier. Once rumbled, the monstrosity shape-shifted into a terrifying metallic construct that was soon put down with some brutal fire from our vigilant squad mates. The ability to blend in amongst normal humans should make facing off against these infiltrators a tense and refreshing experience.

We were then shown a couple of battles, which started out with the team taking cover against a group of aliens hiding behind an impenetrable shield. Tried-and-tested cover-based FPS mechanics should come as second nature to shooter junkies, but it soon became apparent that each encounter is more akin to a tactical puzzle game instead of a straight gunfight. Holding down the command interface button slows the action down to a crawl and brings up a radial command inferface (that's overtly reminiscent of Mass Effect's command wheel), from which individual squad powers and rules of engagement can be triggered on the fly. Commanding the team to deploy their power shield and attract attention using a firework display caused the alien invaders to focus their firepower (and shield) on their location; letting Carter circle around the periphery of the battlefield and destroy the generator with a few well-placed shots. Once the shield was down, the aliens dropped in short order. Naturally players will need to use their squad's unique abilities to find their own solution to the shield 'puzzle,' which should significantly enhance replayability.

Once the fight had concluded, 2K informed us that the otherworldly metallic crystals thrusting out of the ground is known as Corruption, and can be used by the Outsiders to dynamically alter the battlefield in terms of topography, choke points and cover. We'll need to wait for some more practical demonstrations, but I'm sure you get the gist of it.

The second battle was a lot more tense thanks to the aliens deploying an automatic turret. The developers noted that all-out firepower and clever use of cover would be effective at destroying the turret outright, but after flanking the automaton and neutralising its defenders, Carter was able to demonstrate his most important command ability. Alien technology can be captured if players keep them intact, resulting in a harder fight with a huge payoff at the end. This turret, 2K explained, could be picked apart by the R&D lab rats at the end of the mission for significant research bonuses... though as a massive squad of over a dozen interlopers joined the fray, we discovered that captured tech also provides a serious nerve-wracking quandary.

Rather than keeping the device for massive long-term research boosts, Carter can alternatively opt to deploy it straight away for short-term damage output. Redeploying alien weaponry is as simple as entering the command interface and selecting a drop point, and the turret soon teleported onto the battlefield and annihilated the surprised aggressors with surgical precision. Balancing long-term gain with immediate combat applications should provide a unique twist on the combat as well as a higher level decision rarely seen in the genre.

Finally, we were introduced to the menacing Titan (not the Goliath, thanks Kevin). This enormous floating disc turns the battlefield into "electric death," forcing the squad to hide under cover and evade its devastating particle beam cannon. Taking down these floating fortresses will be a major challenge depending on your loadout, but once again, 2K Marin were keen to demonstrate XCOM's capture mechanics in action. Weakening the behemoth with power drain attacks and indirect fire is infinitely more dangerous than blowing it up outright, so after a couple of truly nail-biting minutes, the Titan was finally subdued enough to teleport it back to the labs. Sure, keeping it on ice would have yielded an veritable bounty of new weapon and armour technology at the end of the mission... but hey, we were here to "see stuff blow up", right? Carter redeployed the war machine against a huge phalanx of Outsiders, and any thoughts of the lost potential was soon forgotten thanks to the technicolour murder that poured onto the hopelessly panicking aliens. Job done.

2K Marin still have a lot to prove, and only time will tell whether they have what it takes to breathe new life into the classic franchise. All we know is that they're finally headed down the right track.