AI director
Also said as Director, Dramatic pacing, Adaptive pacing
A system above the enemies that watches how the players are doing, and decides when and where threats appear, to make the tension rise and fall.
Fixed encounters are the same on every play, and a steady stream of enemies goes numb. A director can give a group a rest when they need one, and that is what makes the next attack land.
Say it
“Track intensity from damage taken and enemies nearby. Above 75%, stop spawning for 30 seconds or until they move on, and do not spawn anything in their view.”
Where you’ve seen it
Left 4 Dead's director estimates each survivor's intensity, then cycles through Build Up, Sustain Peak, Peak Fade and Relax, with Relax lasting 30 to 45 seconds with few threats, in Michael Booth's account.
Not to be confused with difficulty adjustment
Adjusting difficulty aims to keep the game beatable. A director aims at pacing: it can leave strong players alone for a while because they need the quiet too.