For those of you with fond memories of the original X-Com, which was released back in 1994 when men were men and video games were designed to be as punishing and unforgiving as possible, this game captures the challenge of the original. For those of you who prefer your games to pleasantly shepherd you toward the end as the easy challenges fall under your mighty might, this game can still work for you.
The gameplay is wonderful. You are the commander of the entire organization and are responsible for everything from hiring soldiers and managing the funding to commanding the boots on the ground. The combination of large-scale strategy that really works well and is fun to the street-level tactical game where you position your squad and choose the targets and hope, hope that you succeed with the 73% chance that your sniper has to kill this alien before the turn or else the grey jerk will have the drop on your medic and will probably kill him. The point is, everything rests on you.
And, that medic? If he dies, he is dead. He will never come back, and you will have to figure out what to do next. In fact, your entire squad can die, and you will just lose the mission, not the game. You will miss the soldiers, but you can always hire some more. And then, take the time to train them and, hopefully, not get careless in the next fight.
There are two things that make this game work so well for the part-timer. Since the game is turn-based, you can save at any point (unless you are playing Ironman, but more on that in three sentences). The other thing is the incredible freedom to choose exactly how difficult you want to make the game. You can slide the scale from certain victory to almost certain defeat. There is even a mode called Ironman (See?) that keeps you from having access to your save file, so there are no do-overs. The fact that the same game can be either delightfully casual or disturbingly hardcore means that absolutely anyone who wants to play it should be able to.
XCOM is a game that manages to evoke the punishing games of yesteryear, without alienating the gamers of today. While I apologize for that terrible pun, I would like to recommend that you give this game a shot. The generous save system means that you can fit this into almost any gap in your schedule, and the game is more than worth your valuable time.