Tier

In Act of Aggression, tiers refer to the tech level of a base and the tier unlock upgrade required to produce a unit or structure. At higher tiers, more advanced and powerful units are available. The highest tier of each faction unlocks their superweapon. All factions upgrade their ties in a centralized headquarters.

United States Army

The United States Army increases in their tiers through the DEFCON system. At the beginning of the game, the US Army starts at DEFCON 3 (tier 1). At DEFCON 3, the US Army has only access to more basic infantry units (such as the U.S. Marine and Javelin soldier), light vehicles (such as the survey team and the Humvee), light base defenses, and medical and logistical support. At DEFCON 2 (tier 2), the US Army has access to more expensive units like attack helicopters, fixed-wing aircraft, and heavier vehicles as well as more fortifications. At DEFCON 1 (tier 3), the US Army unlocks units and structures which require rare earth elements to produce, specifically Peacekeeper，HIMARS, and Patriot.

Chimera

Chimera is limited by three protocols, SPEAR, SHIELD and SWORD. Chimera starts the game with Spear Protocol units, such as the basic Sentinel turret, the SPEAR vehicle bay (produces the likes of Puma), the Barracks (with only SAS and FÉLIN). The SHIELD and SWORD Protocols unlock defense and offense-related assets respectively, and can be purchased in any order. SWORD is necessary for producing the likes of Rhino and the Puma's Spike-LR missiles, whereas the SHIELD protocol gives access to the powerful Pantsir AA vehicle and the Outpost's repair module. Some like the Syntech lab and Anti-Ballistic Center require both to be purchased first.

Cartel

As opposed to both the Chimera and United States Army, Cartel only has two tech tiers, Private Military and Black Ops. Cartel starts the game with Private Military unlocked by default, having access to fundamental units and structures like Scorpio/Otomatic in Vehicles Bay, Contractor/Viper/Grinch in Barracks and the Artillery Turret. Many of Cartel's advanced options are exclusive to Black Ops, such as their Air Control Center, Tokamak Generator and Stealth Lab. Cartel tends to have more units locked by individual options, such as Spectre/Vanguard and Accelerator requiring Stealth Lab while Shershen requires a Barracks with a Prison Module.

See also

• Resources