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.
Gave ship orders 15 times.
Watched all event scenes.
Kept your promise with Riley Miller.
Obtained A ranks on all missions.
Obtained all tank parts.
Obtained all ship parts.
Recruited all squad members.
One of your classes was promoted to Paragon status.
Completed Chapter 18, and ended Belgar's dark ambitions.
Defeated 1000 enemy units.
Rescued 10 allies in critical condition.
Learned all orders.
Completed Chapter 17, and witnessed the end of the war.
Completed Chapter 15, and defeated both Walz and Crymaria.
Gave orders 15 times.
Completed Chapter 11, and made it past the Sea Fortress.
Developed the Hafen into a heavy tank.
Earned 1,000,000 DCT cumulatively.
Gave direct commands 15 times.
Defeated 15 enemy aces.
Obtained A ranks on 20 missions.
Completed Chapter 7, and rendezvoused with the Centurion.
One of your classes was promoted to Elite status.
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.
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.