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