The Joker's thesis, stated directly by the game — the claim that any person, subjected to sufficient pressure, will break. The game takes the thesis seriously enough to build an entire alternate universe around it, to ask what happens if Superman has his bad day and the Joker turns out to be right. The one bad day is the Metropolis bomb, Lois's death, the nuclear detonation that turned Superman's grief into the Regime.

What the game's resistance argues is not that people cannot break — they can, the alternate heroes prove it — but that breaking is still a choice, that the bad day creates the temptation but the person still decides whether to act on it. Batman's bad day is as present as Superman's. He made a different choice.