We got the chance to check out XCOM: Enemy Unknown at PAX East 2012 and Eric "The Boss" Eckstein let us know why the game's cinematic experience is so riveting:
"In the middle of issuing orders to a soldier, we cut to an in-game cutscene, eyeing Sectoids who are clustered, almost as if feeding, around a human corpse. They scatter off, and their "turn" begins, seamlessly after the cinematic ends. This happens again later when we meet another race of aliens, Mutons, who lie in wait inside a gas station, and once more as a Beserker smashes through a wall to take out one of our squad mates. In every instance, XCOM takes what was once a fairly standard reveal within a fog of war to a new level, making us feel fear or curiosity."
Check out or full XCOM: Enemy Unknown preview.