"You can fail in a sports video game; you might not win the championship," DeAngelis said. "That's not a staple in the current gaming landscape, except for sports games. In traditional games, you're used to losing and then restarting. But it's OK if you lose a mission in XCOM. In fact, you're going to lose missions in XCOM."
I've written before that only sports move forward from a decisive loss—which is not exactly true, as strategy titles feature this outcome constantly without jeopardizing the overal goal. Still, DeAngelis is right. You may undo all of your mistakes by reloading quicksaves, and reach the end of XCOM without a single defeat, but it would feel as inauthentic as an 82-0 season in his other favorite game, NBA 2K13.
Failure in other mission-based narratives in gaming either force you to retry or, simply put you back out into an open world to acquire whatever you need to win or advance—whether that's experience points in an MMO or your next wristband in Forza Horizon or whatever. If it doesn't count, it can be undone.
Failure is permanent in XCOM—you can see it any time you visit the memorial of dead soldiers in the barracks, or when a nation is at maximum panic level, and you can't give it a satellite, and the mission there is simply too dangerous to pursue.
"When you lose missions or lose soldiers, or lose a nation, you've got to surge forward and have your coach give a rallying speech," DeAngelis said. "It's an important component of the original."