Here is the full list of all 21 LOOPERS achievements.
Read “Prologue.”
Collect all trophies.
Read “Old Friends, Late-Night Hunting.”
Read “Strange Girl, Stranger Events.”
Read “Sagashi-Onna, Descent Into Madness.”
Read “Lost Souls, Endless Loop.”
Read “Welcome to the Spiral, Welcome to the Loopers.”
Read “Living Large, Dying Inside.”
Read “Treasure Hunt, Ferris Wheel Fireworks.”
Read “Mia's Request, Looper Rehab.”
Read “Sleeping Beauty, History Repeating.”
Read “Time Capsule, A Little Miracle.”
Read “A Secret Wish, Final Fireworks.”
Read “Best of Friends, Time To Leave.”
Read “Confusion, A Botched Miracle.”
Read “What I Wished For, End of Eternity.”
Read “Extra-Special Spell, Dinosaur Eraser.”
Read up until “The Real Treasure.”
Complete the chapters.
Complete the gallery.
Complete the soundtrack.