Here is the full list of all 18 Subject Debris achievements.
Press Start new game for the first time
Press button Continue for the first time
First time interact with something!
Meet Rizacen
Meet Lilyas
Meet Mete
Meet Chadre
Meet Statia
Kill Lilyas
Kill Statia
Beat Chadre
See the truth
Complete 1 ending
You defeat Humasaurus - The strongest monster in this game
Defeat the zombie
Defeat Crawlis
Defeat Goumoured
Meet Illusia