Here is the full list of all 40 OPUS: Echo of Starsong achievements.
Complete the game
Enter Chapter 5
Not getting hit once when landing on Banshee
Be honest to Eda
Read the message
Enter Chapter 4
Thank Remi
Never been hit once by the space debris
Fully deck out Red Chamber
Acquire over 3 Tales of Failure
Trust in Remi
Completely run out of fuel twice
Visit over 50 locations in Thousand Peaks
Die twice in a playthrough
Decided not to send out the letter
Acquired over 100 items
Enter Chapter 3
Visit over 30 different locaitons
Let Eda decide
Visit over 10 locations in Thousand Peaks
Visit over 10 different locations
Acquire over 20 items
Help to return a favor
Enter Chapter 2
Not listening to Kay's advice
Enter Chapter 1
Complete the game without failing once
Complete the game without resonating with the wrong starsong
Protect as Jun
Complete the game in 8 hours
Complete all the East Ocean puzzles without any mistakes
Visit all locations
Visit all locations in Thousand Peaks
Acquire over 20000 credits
Acquire all items
Be kind to Bones
Shoot the dart 10 times
Enter Chapter 2: Part Two
Enter Chapter 3: Part Two