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.
Obtained A ranks on all missions.
Watched all event scenes.
Kept your promise with Riley Miller.
Obtained all tank parts.
Obtained all infantry weapons.
All of your classes were upgraded to max level.
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.
Learned all orders.
Completed Chapter 17, and witnessed the end of the war.
Gave ship orders 15 times.
Completed Chapter 15, and defeated both Walz and Crymaria.
Completed Chapter 11, and made it past the Sea Fortress.
Defeated 1000 enemy units.
Gave orders 15 times.
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.
Gave direct commands 15 times.
One of your classes was promoted to Elite status.
Rescued 10 allies in critical condition.
Completed Chapter 4, and won the battle of Siegval.
Completed a squad story for the first time.
One of your squadmates was promoted to Corporal.
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.