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.
Obtained all infantry weapons.
All of your classes were upgraded to max level.
Watched all event scenes.
Obtained A ranks on all missions.
Obtained all tank parts.
Recruited all squad members.
Obtained all ship parts.
Kept your promise with Riley Miller.
Defeated 1000 enemy units.
Gave direct commands 15 times.
Gave ship orders 15 times.
One of your classes was promoted to Paragon status.
Learned all orders.
Completed Chapter 18, and ended Belgar's dark ambitions.
Gave orders 15 times.
Completed Chapter 17, and witnessed the end of the war.
Completed Chapter 15, and defeated both Walz and Crymaria.
Defeated 15 enemy aces.
Obtained A ranks on 20 missions.
Rescued 10 allies in critical condition.
Earned 1,000,000 DCT cumulatively.
Completed Chapter 11, and made it past the Sea Fortress.
One of your classes was promoted to Elite status.
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.
Completed a squad story for the first time.
One of your squadmates was promoted to Corporal.
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.