Gear
The player can upgrade their armor to make it better and stronger but these cannot be purchased and are unlocked as the player progresses through campaign mode. The players start with Basic body armor, upgrade to Medium after completing the Afghanistan mission, and are granted Heavy body armor after the Aircraft Carrier mission. Players can also unlock and purchase new face masks that the main characters wear.
Customization
The game allows weapon customization, bought with money earned as the game progresses. Such elements as new barrels, stocks, forend-mounted vertical grips, and extra-large magazines and ammo drums that can be swapped out to give the weapon a unique look and superior statistics. Other modifications include suppressors, a gun-shield, an underslung grenade launcher, or an underslung 12-gauge shotgun.
A firing range feature was proposed that would allow the player to test out their newly customized weapon; however, it was removed as it did not meet the developers' standards.[5]
Vehicles
The original game boasted three different drivable vehicles: a jeep, a main battle tank, and a hovercraft. Gameplay was designed so that one player would drive and the other would fire a secondary weapon like a ring-mounted XM312 heavy machine gun (jeep and hovercraft) or a 120 mm cannon (the tank). The jeep and tank were removed from the final product due to "pacing issues" and the hovercraft was used only in the China and Miami levels.
Online multiplayer
Multiplayer (or "Versus" mode) allows up to four players, with two on each team (similar to the co-op structure of the main campaign). Both teams will compete over objectives on the map such as assassinating a VIP or destroying an objective in order to earn the most money for their side. At the same time, they will also be forced to deal with the opposing team in order to secure their objectives. On August 11, 2011, The Army of Two online servers were shut down by EA, due to lack of players.
Multiplayer for the game was region-locked. Players with the European, American or Asian version of the game could not play with each other.[6]
There are three multiplayer game types: Warzone, Bounties, and Extraction.
In Warzone, the primary and secondary objectives are randomly generated and they may vary greatly. One team might need to get to a certain place and defend it, while the other team tries to destroy it, shoot down the chopper, blow up a jeep with its gunner, transport wounded soldiers to the extraction point, assassinate V.I.P's, etc.
Bounty has the player hunt down the leader of the hostile forces on the map in exchange for a sum of money.
In Extraction the objective is to rescue randomly spawned V.I.P.s or P.O.W.s to a safe location.
Also, every map contains cases of intelligence documents that the player can seek out for extra cash.
Character customization is not possible in the multiplayer portion of the game but the player can buy preset sets of weapons, upgrade the characters body armor and the amount of ammo he can carry. Players need to be careful while shopping though since the team with the most cash in the end wins.