Here is the full list of all 36 Valkyria Chronicles 4 achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Learned all orders.
Defeated 1000 enemy units.
One of your classes was promoted to Paragon status.
Completed Chapter 18, and ended Belgar's dark ambitions.
Completed Chapter 17, and witnessed the end of the war.
Obtained A ranks on 20 missions.
Completed Chapter 15, and defeated both Walz and Crymaria.
Defeated 15 enemy aces.
Gave direct commands 15 times.
Completed Chapter 11, and made it past the Sea Fortress.
Earned 1,000,000 DCT cumulatively.
Gave orders 15 times.
One of your classes was promoted to Elite status.
Developed the Hafen into a heavy tank.
Completed 10 missions without anyone in critical condition.
Completed Chapter 7, and rendezvoused with the Centurion.
Rescued 10 allies in critical condition.
Completed Chapter 4, and won the battle of Siegval.
One of your squadmates was promoted to Corporal.
Defeated an enemy ace for the first time.
Completed a squad story for the first time.
Learned an order at the Mess Hall for the first time.
Used R&D Facility for the first time.
Obtained an A rank on a mission for the first time.
Obtained all achievements.
Obtained all decorations.
Kept your promise with Riley Miller.
Watched all event scenes.
Recruited all squad members.
Obtained all infantry weapons.
Obtained all tank parts.
Obtained all ship parts.
All of your classes were upgraded to max level.
Obtained A ranks on all missions.
Gave ship orders 15 times.
Triggered a Last Stand 15 times.