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