Proud to have XCOM: Enemy Within as this year's Oktoberfest sponsor, as the festival approaches, we investigate what lies within the expansion to last year's award-winning XCOM: Enemy Unknown.

A job within the XCOM organisation is, it would seem, a job for life as this huge expansion pack brings a range of new enemy threats for soldiers to sink their guns into. Having discovered a valuable new alien resource - the highly volatile MELD which has been released into the landscape, XCOM has gained access to new research facilities including a Genetics Lab and a Cybernetics Lab.

Yup, XCOM just got sci-fi supersized.

The Genetics Lab allows Gene Mods to physically enhance operatives' abilities by offering chest, brain, eyes, skin and leg augmentations that can be swapped out and changed whenever back at base, which sounds rather grim in medical terms, but adds a whole different flavour to the now familiar gameplay. Snipers can now leap up to take position on rooftops in one giant jump whilst Assault class soldiers can heal themselves over time. Elsewhere back on the Ant Farm base, Mechanised Exoskeletal Cybersuits, or MECs, brings a whole new class of robotised soldier to the party that packs a powerful rocket punch and can be loaded up with flamethrowers and grenade launchers.

XCOM's alien adversaries have never been an easy push over, especially the larger variety who singularly often match a entire team's tactical and strategical prowess. When playing one of the 47 new maps in Enemy Within, guiding our newly enhanced crew as they picked their way towards the enemy whilst our MECs crashed through towards the front line of the battle, our renewed hope of securing a smashing success were cruelly dashed with the arrival of the Mechtoid. Of course! Those slippery, grey, almond shaped pests are able use the MELD to equally devastating, mechanised effects. The result was that the battle flowed quicker than expected, and though there were more tactical options available, making the right decisions in the exploding heat of the moment required greater skills in planning and execution.

This new alien technology also heralds the arrival of a new threat; one that could cripple XCOM. Meet EXALT. Operating within hidden cells across the world, they are a rebel organisation sympathetic to the alien invaders, with an eye on claiming some alien technology for themselves in order to thwart XCOM activity.

XCOM must now also balance the threat of the human enemy within.

Blanketing an extra layer of strategic panic over the game, players must initiate covert missions to neutralise individual cells and recover vital intelligence needed to locate the EXALT base. The cells are not always visible so paying for scans to reveal EXALT locations is a new drain on finances. Able to send out only one covert operative (complete with new khaki uniform including chunky knit sweater, jeans and heavy boots) at a time, after 6 days of secret detective work, players might be called to send their teams in to either protect and recover data from getting in EXALT's grubby orange masked, leather gloved mitts, or protect the special operative from rebel attacks as they carry out their task.

Having scattily succeeded in assisting a man in the field (a German with an authentic, literally translated voice as all the operatives now speak in their native language rather than just American), we had just a couple of turns needed to escort the man home; dragging the severely depleted, bedraggled and increasingly short on ammo team back to base. Flanked on all sides, EXALT sent a final wave of white shirted, high black trouser wearing big gunners to make sure we didn't make it home, landing a giant rocket on our exposed heads. The muddy forest building site map where the carnage took place was tight at the landing spot with few trunks as coverage, and the operative had already spent all he had weaving across the wider open site. It wasn't long before he too joined our ever increasing list of The Fallen; the taste of perma-death is still a bitter one.

The maps in this expansion are so much more detailed, complex and realistic, with UFOs now able to land in urban areas or farms, not just out in the middle of the woods. Pile on new weapons to research plus new multiplayer maps with new units and abilities, and it all equals a refreshed, engaging and satisfying XCOM experience.

XCOM: Enemy Within is due out on November 15th on PC (which requires the original XCOM: Enemy Unknown to run), on Xbox 360 and on Playstation 3.

Get in the mood for XCOM: Enemy Within early with our Oktoberfest #XCOMallnighter on Saturday 12th Oct