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