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.
Watched all event scenes.
Kept your promise with Riley Miller.
Obtained A ranks on all missions.
All of your classes were upgraded to max level.
Obtained all tank parts.
Obtained all ship parts.
Recruited all squad members.
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.
Gave ship orders 15 times.
Rescued 10 allies in critical condition.
Defeated 1000 enemy units.
Completed Chapter 15, and defeated both Walz and Crymaria.
One of your squadmates was promoted to Corporal.
Gave orders 15 times.
Completed Chapter 11, and made it past the Sea Fortress.
Earned 1,000,000 DCT cumulatively.
Defeated 15 enemy aces.
Obtained A ranks on 20 missions.
Developed the Hafen into a heavy tank.
Completed Chapter 7, and rendezvoused with the Centurion.
One of your classes was promoted to Elite status.
Gave direct commands 15 times.
Completed a squad story for the first time.
Completed Chapter 4, and won the battle of Siegval.
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.