The Daily Conflict Update

The daily conflict update added a host of game "mutators" of which the player can play one in 24 hours in a rotation. Each mutator adds or changes a rule/rules of the game according to a theme, I.e. "Dirty War" will change it so that every nation destroyed in action will immediately become uninhabitable, as if it was hit by a Dirty Bomb. Once the player beats the scenario (wins the game), the mutator is unlocked for singleplayer to be played even when not the current mutator in the rotation. That way, a player can unlock every mutator in the game by winning the respective scenario each day.

The Daily Conflict Update came as a result of the Classic Update, which allows for easily setting and changing rules in a modular setting, essentially turning the "normal" game rules into just another mutator, if you so will.