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