Here is the full list of all 30 A.R.E.S. Extinction Agenda EX achievements worth 400 gamerscore.
Finish the game with Ares
Finish the game with Tarus
Finish every chapter without using repair
Achieve character level '4'
Achieve character level '5'
Achieve character level '6'
Beat Carrion with both Ares and Tarus
Beat Zypher Pod with Ares
Find the drone repair bay
Beat the boss in chapter 5 with Ares
Beat Zytron Walker, Zytron Trooper and Zytron Booster with Tarus
Beat the boss in chapter 5 with Tarus
Perfect the Goliath boss fight
Perfect the Carrion boss fight
Perfect the Zypher Pod boss fight
Perfect the Sentinel boss fight
Perfect the boss fight in chapter 5 with Tarus
Perfect the boss fight in chapter 5 with Ares
Perfect the Prime Guardian boss fight
Perfect the Minos Cannon boss fight
Acquire all abilities and weapons
Collect all the Data cubes
Collect all Upgrade chips
Break the enemy’s shield with Plasma Shock or Lockdown
Achieve 99 attack combo
Upgrade one of your weapons to its maximum level
Upgrade every weapon and ability to its maximum level
Destroy 5 or more enemies, at once with Solar Strike