XCOM and XCOM 2, are two turn based tactics game that rely on randomly generated levels and environments for the different missions the player takes on. As a result the game’s difficulty curve has a slight slant of randomness to it, as the game’s various walls of cover can be a help or a hindrance. Despite this element of randomness, the game tries to keep the various levels relatively balanced by providing efficient cover for both the player and the enemies.
The XCOM series’ main point of influencing difficulty, is by slowly ramping up the difficulty of enemies and introducing them at a pace, where if the player never focused on improving their soldiers, they would easily be overrun. So the game starts off an arms war, as you race to keep up with the ever increasing hostility and effectiveness of the alien encounters, up until XCOM’s endgame, where the last new enemy is introduced and your soldier’s are equipped with the best gear. At this the main point of XCOM’s difficulty comes from the player’s battle strategy and how they react to the enemies’ own movements and approach.
A major mechanic that is employed in each level of XCOM, is the “Fog of War,” the areas of the map that are shrouded in darkness and hide anything within. Because the player is left with limited visibility of only the areas surrounding the player’s squad, they must advance carefully into the unknown with the fear of running into a crossfire. This adds a staple of difficulty to the XCOM series, as the player must be vigilant and prepared to deal with an unsuspecting ambush or moving to what was supposed to be safe cover, to all of a sudden becoming flanked by an enemy squad you had no idea was there.
Ultimately XCOM is a clever game about putting together a strategy and knowing how to counter an opponent’s own, when it exposes your own plan. So the player must constantly keep on their toes, as a sudden appearing squad of aliens on the rear flank can prove deadly to even the most fool-proof plan.