Setting Armored Core 4 takes place in a futuristic earth in which global government instability has led to super corporations taking their place in the world. You play a role as a pilot for one of these comglomerates and must take a number of various missions which take you to various locations around the world, from city ruins in a desert, to fighting submarines in the artic and even underground facilities. The player pilots his mech against a variety of combat hardware such as tanks, helicopters, destroyers to even enemy mechs such as your own. Other missions require the player destroy large buildings such as a huge reactor.
Gameplay Singleplayer Missions Players playthrough the game by doing a variety of missions set out over 5 chapters. A ranking system is also intergrated within the game, giving the player feedback on how well he did on the mission he played through. Ranks range from E to S and take into account the time taken, ammunition used and damage the player recieved. Achieving S ranks in the game award the player with a bonus to his or her mechs customizability. Players gain credits through missions to buy new weapons and parts for their mech. Missions, if completed poorly, can also enable the player to lose credits. As such, players are required to keep within the damage, time and ammo expectations of each mission in order to avoid being penalised. Conversely, better perfomance grants the player bonuses to their standard credit reward for completing each mission.
An explosive battle over the ocean When on the actual mission the player controls his mech from a 3rd person view and can have up to seven different weapons. The players mech has the ability not only to run on its legs but can also thrust up in the air and allow flight if the mech is configured properly. Mechs can also activate an overboost which zooms the players accross the level providing they have a mech built with high energy stored. The player can choose which weapons to fire based on which arm button is pressed on the controller, additionally shoulder-mounted weapons can be selected taking place of the respected arm weapon. One can also choose to detach a number of the players weapons for whatever reason to reveal backup weapons such as a handgun or a energy blade.
Mech Customization Mech customization has always been a central theme to the franchise and it continues to be in Armored Core 4. Different mech loadouts can be created to match the players playstyle additionally certain configurations can be made to complete certain missions which may require it. Different mech builds can be stored in the game menu and be called upon to be automatically built providing the player's console has enough storage capacity.
Players can customize their make making it weild a variety of weapons ranging from energy blades, sniper rifles to even bazookas and large energy cannons. The actual mech's body parts can also be swapped around with each body part having different stats. Additionally the overall mech can be customized by assigning FRS points to stats such as thrust output to raise boost time or arm stability to raise weapon accuracy. Finally a paint job and logo design creator can also be played around with if the player wishes to do so.
Online play The online play in Armored Core 4 allows players to have the standard deathmatch and team deathmatch on a choice of half a dozen maps. Players can use their own custom built mechs from the single player and even trade mech schematics with others if they wish to do so.
As of the 16th of May 2009, the online populace on the Xbox 360 version of the game is rather light as the games sequel Armored Core: For Answer has been released.
Technical Online player requires players to download Regulation Files which serve as game patches which fix various inbalance and bug issues. As of 16th of May 2009, 1.60 is the latest regulation file. Armored Core 4 requires 5.9GB of space to install on an Xbox 360 HDD.