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 all infantry weapons.
Obtained A ranks on all missions.
All of your classes were upgraded to max level.
Obtained all tank parts.
Obtained all ship parts.
Watched all event scenes.
Recruited all squad members.
Gave ship orders 15 times.
Kept your promise with Riley Miller.
Defeated 1000 enemy units.
One of your classes was promoted to Paragon status.
Completed Chapter 18, and ended Belgar's dark ambitions.
Completed Chapter 17, and witnessed the end of the war.
Gave direct commands 15 times.
Learned all orders.
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.
Completed Chapter 7, and rendezvoused with the Centurion.
Obtained A ranks on 20 missions.
Defeated 15 enemy aces.
Completed Chapter 4, and won the battle of Siegval.
One of your classes was promoted to Elite status.
Completed 10 missions without anyone in critical condition.
Rescued 10 allies in critical condition.
Completed a squad story for the first time.
One of your squadmates was promoted to Corporal.
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.