Although this title brought very little in the way of innovation, the single player campaign's story is where "Spec Ops: The Line" shines. Based on Joseph Konrad's "The Heart of Darkness" (the same book that inspired Francis Ford Coppola's "Apocalypse Now!") Spec Ops The Line in an experience that explores the more grizzly and dark side of modern warfare. The main themes explored in the story revolved around Post Traumatic Stress Disorder and the use of white phosphorus as a weapon of war (which was a huge ethical question for coalition forces during the 2003 Iraq war). Unlike C.O.D. or Battlefield, Spec Ops draws players in with expectations of being a generic war game and flips those expectations right on their head, as many of the games' enemies are U.S. soldiers (and you're playing as a Delta Force captain). The game also broke the fourth wall and addressed players directly through a clever use of loading screen messages and game mechanics.
As players progress through the game and died at certain points, they'd notice that the loading screens would start saying really uncomfortable stuff like;
"This is all your fault,"
"How many Americans have you killed today?"
"There is no difference between what is right and what is necessary,"
and "Cognitive dissonance is an uncomfortable feeling caused by holding two conflicting beliefs simultaneously."
That final message (about cognitive dissonance) is essential for the player. Gunning down American G.I.'s and sandstorm survivors whilst knowing in the back of the mind that something is wrong about all this. The real zenith of the game is when you finally meet the Colonel. When the final twist comes, a couple of plot holes do reveal themselves but I forgive it because the developers had the courage to address these themes. War is not a game. Being a soldier in today's military is one of the most stressful jobs out there and we need games like this to remind us that soldiers are human beings, not unthinking robots.