4. Easy to Learn, Hard to Master Gameplay Mechanics
So youve just deployed a team of four (which will rise to six over time), and you set about exploring the evacuated city block ahead. You send two of your guys directly forward to scout out potential threats, and place another two down adjacent alleyways, so as to maximise your viewpoint on whatever may be in wait. A team of two small orb-headed aliens approach from the opposing direction and take cover across from your squad, waiting for your next move. Quickly and efficiently you instruct your squad to take care of them, and after a few complete misses (they are rookies after all), said orb-headed-ones are green splats on the pavement. Cut to another hour or so into the mission and this tactic seems to be working well enough, until you find yourself flanked on both sides by increasing numbers of the little blighters. Within seconds your team is decimated by way of searing-hot gunfire, and you wonder where it was you went wrong, and how you could have prevented this outcome. You should have used Overwatch, the act of putting one whichever one of your guys into a sentry-like mode, who will fire upon any who enter their vicinity. Its this powerplay of carefully creeping forward whilst constantly being aware of what might happen, that allows for more advanced play, and is what lays the groundwork for the newer elements such as gene modification to build upon. You see, your team's field of view is limited only to your immediate position, so see that seemingly abandoned building just ahead ripe for the door-smashing? There could be a platoon of laser-wielders on the other side who will instantly rip you in half, therefore the increasingly tactical rub is who do you choose to go in first, how do you set up for what might spill out of said building, and what are you going to do as a contingency plan if all this fails? Such is the beauty of XCOM, and deciding all these things, alongside rolling with a augmented punch, is what will keep you glued to the game until you see your troops safely home.