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