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