Armored Core: For Answer is the 13th installment in the Armored Core series. Ten years after the National Dismantlement War, the planet has become extremely polluted and is falling apart at the seams. "The League", a organization of corporations, have decided to build the "Cradle System" high above the Earth in order to protect civilians, but the system running the habitats only make things worse down below on the surface. Using these platforms, they run the planet below using a high-tech army to dominate and control. Hearing of this, a group of surface dwellers form the rebel group called "The Line Ark" attack the "The League" in an attempt to bring order out of chaos. In this another mysterious faction called the "ORCA" has surfaced, their motives unknown to both sides.

The player assumes the role of a mercenary for hire, picking which side they would like to work for. They are then given a mech and equipped with the most advanced weaponry and must complete missions in an attempt to win battles and ultimately win the war for their side.

The gameplay consists of traveling through levels, destroying various enemies and completing certain objectives that include attacking certain enemies, protecting allies or acquire technology. Players must also battle huge mech bosses in order to advance to other levels and can also customize their mech in a various amount of ways, ranging from color, weapons, etc. The viewpoint is from behind the player, using the analog stick to move the camera and view the surrounding area.

There is also multiplayer capabilities including co-op that a friend can join in and help them out at any time during a game. Players can also go online, using their respective service, to battle friends in deathmatches.