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.
Completed 10 missions without anyone in critical condition.
Defeated an enemy ace for the first time.
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.
Obtained all achievements.
Obtained all decorations.
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.
Completed Chapter 17, and witnessed the end of the war.
Completed Chapter 18, and ended Belgar's dark ambitions.
Kept your promise with Riley Miller.
Defeated 15 enemy aces.
Defeated 1000 enemy units.
Rescued 10 allies in critical condition.
Watched all event scenes.
Completed a squad story for the first time.
Recruited all squad members.
Obtained all infantry weapons.
Developed the Hafen into a heavy tank.
Obtained all tank parts.
Obtained all ship parts.
Learned all orders.
One of your squadmates was promoted to Corporal.
One of your classes was promoted to Elite status.
One of your classes was promoted to Paragon status.
All of your classes were upgraded to max level.
Earned 1,000,000 DCT cumulatively.
Obtained A ranks on 20 missions.
Obtained A ranks on all missions.
Gave ship orders 15 times.
Gave direct commands 15 times.
Gave orders 15 times.
Triggered a Last Stand 15 times.