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 tank parts.
Obtained all infantry weapons.
Watched all event scenes.
Obtained A ranks on all missions.
Recruited all squad members.
Triggered a Last Stand 15 times.
Gave direct commands 15 times.
Gave ship orders 15 times.
Kept your promise with Riley Miller.
Completed Chapter 17, and witnessed the end of the war.
Completed Chapter 18, and ended Belgar's dark ambitions.
Obtained all ship parts.
Learned all orders.
One of your classes was promoted to Paragon status.
All of your classes were upgraded to max level.
Completed Chapter 4, and won the battle of Siegval.
Completed Chapter 7, and rendezvoused with the Centurion.
Completed Chapter 11, and made it past the Sea Fortress.
Completed Chapter 15, and defeated both Walz and Crymaria.
Defeated an enemy ace for the first time.
Defeated 15 enemy aces.
Defeated 1000 enemy units.
Rescued 10 allies in critical condition.
Completed a squad story for the first time.
Used R&D Facility for the first time.
Developed the Hafen into a heavy tank.
Learned an order at the Mess Hall for the first time.
One of your squadmates was promoted to Corporal.
One of your classes was promoted to Elite status.
Earned 1,000,000 DCT cumulatively.
Obtained an A rank on a mission for the first time.
Obtained A ranks on 20 missions.
Completed 10 missions without anyone in critical condition.
Gave orders 15 times.