From the first moment you’re given control of your mech in Armored Core 6, there’s a perplexing and completely unusable “Expansion” slot in the lower left of your screen.
Although most other systems in the game are explained with a helpful tutorial as they’re introduced, especially if you take on the optional mercenary training, it’s easy to miss the Core Expansions and their function entirely.
Given their utility in combat when you do finally have access to them, though, passing up Expansions would be a grave mistake for any pilot.
What are Core Expansions in Armored Core 6?
First off, despite that tantalizing HUD element hanging around from the very first mission, you won’t be able to use Core Expansions until you’ve unlocked the Arena and its associated perk system. They’re unlocked as part of the OS Tuning perk system, and are the most expensive (and arguably the most useful) things you can get your hands on through said system. In essence, they’re like ultimates for your mech—if your back’s against the wall or you’re facing impossible odds, smart use of your Core Expansions may just give you the edge you need to snatch victory from the jaws of defeat.
There are four Core Expansions to choose from, listed for your convenience below. Most of them can be upgraded for more charges, and most of them must be activated manually by pressing the left stick and Triangle/Y at the same time—the sole exception to both rules is the Terminal Armor expansion, which triggers automatically upon death and can only ever be used once per mission. In addition, you can only choose one at a time, so make sure your selected Expansion gels with your playstyle.
Assault Armor
Assault Armor is the most straightforward: it’s an area of effect shockwave centered on your AC. It’ll cancel out incoming fire, hit pulse defenses hard, and inflict damage in a wide radius, meaning that if you often find yourself getting swarmed, this is the Expansion to go with. Its limited range makes it ill suited for huge, open battlefields—it’ll really shine if you like getting up close and personal, but dedicated snipers should turn to other options.
Pulse Protection
Pulse Protection is essentially AC6’s answer to the bubble shield from Halo. It’s a big, protective dome-shaped shield that can take quite a lot of punishment, with the drawback of staying right where you deploy it. A slow, heavily armored AC will naturally take advantage of this, using it to add even more resilience to an already beefy health bar.
Related: Why tank builds are the best in AC6
Pulse Armor
Pulse Armor, as opposed to the static Pulse Protection, creates a shield that follows your AC rather than staying in one spot. It soaks up a little less damage than its stationary cousin, but the tradeoff here is being able to keep moving at the same time. If you’re playing a particularly mobile-but-fragile AC, this may well be the optimal choice for you.
Terminal Armor
Terminal Armor is the most expensive perk on offer. Its function makes its price tag far more understandable, though: it’s basically a second life, which will save your AC from destruction once per mission and give you a shield to protect yourself. While it doesn’t restore health or give you any of your precious repair kits back, you can take advantage of this brief window to go for a final push that will destroy the boss before they can destroy you.
Hopefully, you’re now one step closer to putting the finishing touches on your perfect build. Like every other mech component, expect to be changing out your Core Expansions frequently as needed, and don’t forget to delve into the rest of the layered OS Tuning system to get the most out of your very own mech.
