In a some-what controversial move, developer FROM SOFTWARE remodelled some of the basic elements of the Armored Core formula for Armored Core: Nine Breaker. Removed altogether are the storyline-based missions and instead 'training missions' have been added into the game, intending to develop a player's skill at piloting an AC. The game was divided into two modes, Training Mode and Arena Mode. Source: Wikipedia, "Armored Core: Nine Breaker", available under the CC-BY-SA License.