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.
Watched all event scenes.
Kept your promise with Riley Miller.
Obtained all decorations.
Obtained all infantry weapons.
Obtained all tank parts.
Obtained A ranks on all missions.
Defeated 1000 enemy units.
All of your classes were upgraded to max level.
Gave ship orders 15 times.
Recruited all squad members.
Defeated 15 enemy aces.
Rescued 10 allies in critical condition.
Obtained all ship parts.
Gave direct commands 15 times.
Completed Chapter 18, and ended Belgar's dark ambitions.
One of your classes was promoted to Paragon status.
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 orders 15 times.
Obtained A ranks on 20 missions.
Completed a squad story for the first time.
Developed the Hafen into a heavy tank.
Earned 1,000,000 DCT cumulatively.
One of your squadmates was promoted to Corporal.
Completed 10 missions without anyone in critical condition.
Completed Chapter 7, and rendezvoused with the Centurion.
One of your classes was promoted to Elite status.
Completed Chapter 4, and won the battle of Siegval.
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.