Here is the full list of all 39 Death end re;Quest 2 achievements.
Completed all story endings and explored all paths.
Viewed the EX Ending.
Defeated Ao Oni in the Pain Area.
Defeated 1000 enemies.
Used Glitch Mode a great many times.
Viewed most of the main story.
Viewed many story events.
Played the Ao Oni mini-game.
Viewed the True Ending.
Defeated the final boss.
Viewed the Fallen Ending.
Cleared Chapter 10.
Cleared Chapter 9.
Cleared Chapter 8.
Learned 15 of Lily's skills.
Viewed all of the Death Ends.
Cleared Chapter 7.
Learned 15 of Al's skills.
Used Glitch Mode a handful of times.
Learned 15 of Clea's skills.
Cleared Chapter 6.
Learned 15 of Lucil's skills.
Learned 15 of Shina's skills.
Learned 15 of Celica's skills.
Cleared Chapter 5.
Cleared Chapter 4.
Learned 15 of Liliana's skills.
Cleared Chapter 3.
Cleared Chapter 2.
Learned 15 of Rottie's skills.
Learned 15 of Mai's skills.
Viewed most of the sub-events with your classmates.
Entered Glitch Mode for the first time.
Activated Super Knockback for the first time and sent the enemy flying.
Cleared Chapter 1.
Entered Camp for the first time.
Used a Flash Drive skill for the first time.
Activated Knock Blow for the first time.
Activated Knockback for the first time and sent an enemy back.