It should be noted though that changing the difficulty can be done at anytime without starting NG+. NG+ extends Dying Light’s replay value, making it possible to restart the Campaign in a new or same difficulty while keeping character skills, inventory, and collections.
Both story and game completion percentage can also be viewed from the main menu, but only story completion is necessary for NG+ option to unlock. Story completion percentage can be found in the top right corner while the game is paused, next to the current quest and difficulty. New Game +, New Game Plus or NG+ is not to be confused with starting a new save. New Game Plus or NG+ is a feature in Dying Light that is unlocked in the Main Menu under Play → Campaign → Save → Advanced settings, after reaching 100 % story completion.