Threatened by an unknown enemy, the Earth’s governments unite to form an elite paramilitary organization, known as XCOM, to combat this extraterrestrial attack. As the commander of XCOM, you control the global defense team in a battle against a terrifying alien invasion by creating a fully operational base, researching alien technologies, planning combat missions, and controlling soldier movement in battle.
I had long ago received the initial game for free from some Steam pre-order deal a while ago and had pretty much no active interest in it. Given that an expansion was recently released, I figured it was time to play the damn thing.
Now with a game full of content, without encountering a single bug so far, I can easily say this is one of the best strategy game's I've played in a while.
Your soldiers can die and your supporters can abandon the cause. And those people who die; they matter, they level up, and chances are you'll become attached to the badasses that will inevitably rise among the elite ranks of XCOM. You can change their names, their hair, face, race, armor, colors, ect. But not their sex, so no sexy army of alien killing women for you unless you throw all the men out the airlock.
You can turn some of your soldiers into biological marvels or cybernetic titans that literally punch aliens in the face and gun them down with a giant minigun, among other later upgrades. Eventually some can even tap into their psychic potential, to mind-control aliens and so on.
Assuming you have everything, there are generally three stories running between each other. There is of course the base 'save earth' story, the 'triad guy loyal to humanity' and the 'crazy humans determined to fight the system, man.'
At this point I haven't played beyond 10 hours but having seen a playthrough of the base game, I feel I can say its at the very least a must buy during a Steam sale.