Introversion Software previously made a game called DEFCON [official site], a strategy game in which you launch often unprovoked nuclear attacks upon other countries. Global thermonuclear war is the core of the game, and necessary if you’re going to defeat your opponents, but it never revels in the wanton destruction you’re carrying out. As the death toll rises into the millions, the grim reality of what’s happening is gently communicated through the stark white alerts of how many millions have been killed and through the addition of quiet coughing to the game’s soundtrack.
I’ve killed million and millions in DEFCON. I’m not sure I could bring myself to kill just one person in Prison Architect [official site] using update 31’s newly introduced execution chambers. There’s a video below showing how the process works.