Preordering is retarded. You spend $75 on a game that might suck.
I'm waiting for the day that a game like XCOM Enemy Unknown gets fused with Total War and (just for the keks) Mass Effect. That would be awesome.
Imagine : Aliens invade your human galactic empire. They out-tech you and often have superior numbers. Humanity and its armies, provinces and planets are scattered and are having communications issues. Quickly, you prove yourself on the battlefield and become the highest ranking commander.
In the diplomatic scale, you must work to gain the trust of various human states, whilst acquiring funding from other aliens and gathering Mercenaries, Conscripts, volunteers and professional soldiers to form your primary armies.
On the military operational scale, you must organize your forces into very potent army groups , and you must retake planets or subjugate Rebellious human states or traitors who cooperate with the aliens. Due to the nature of the alien superiority in navy, you must be extremely conservative with the fleets you begin with and you must learn to balance taking losses with transporting sufficient troop numbers.
On military strategic, you can guide your forces in very pitched battles, where the odds will almost always be against you. In space battles, you will always be on your toes as the aliens overpower you. They will adapt to the new strategies you attempt to employ in space.
On military tactical, you will often receive rosters of a couple dozen soldiers who are the best of the best. You can assign only a fee at a time for training in the Elite Units. If they fail to meet Elite Unit training standards, they are then relocated as officers or as NCOs into the regular ground forces. These Elite Forces will go on high priority missions, such as assassinating enemy brass, preparing an area for an ambush by the army, sabotaging enemy activity, rescuing VIPs or gathering information.
On the home front, you will often have issues managing a fragile resource network. Rioting will often occur. Your best defense will be conscription, increasing your work force and wise economy management.
In the political world, you must work to ensure that the Human Galactic Interests Council (HGIC, often pronounced Aych-Gick) is in favor of continuing a stream of funding for your military forces. You must also ensure that no usurpers arise, you must work to ensure that the political parties are very agreeing and in a compromise manner when possible. At certain points, you will be given the option to lead a military coup. Keep in mind that a Dictatorship is great for eliminating politics, but it can be vicious to your Home Front.
Perhaps most important would be your Profile Archive. Here you can overview various statistics of important people of both alien and human (all aliens, that is, not just the invading aliens). You can look at reputation, how good they are at their line of work and what specializations they express.
It's also important to keep track of your own stats and track record. If you lose a lot of pitched battles, leave some planets defenseless, or suffer a crushing blow in space, your Home Front will suffer, many alien races will stop supporting you, political factions will start usurping, the HGIC will become more divided, and planets will start declaring independence.
The game is very rewarding however. If you can keep up the victories, if you make good decisions, if you follow proper pursuits and if you can be a good mediator for some of the warring aliens, you will put Humanity at ease, your soldiers will fight hardier and your funding will be boosted.
It really depends on your skill, and your ability to react to such a vastly overpowering enemy.