Here is the full list of all 8 Soul's Spectrum: Awakening achievements.
Unlock the Skeleton Form.
Unlock the Umbra Form.
Unlock Anima's Blink.
Reach the first ritual in less than 150 steps.
Unlock the Human Form.
Interact with all the characters.
Finish the Prologue.
Finish the Prologue with less than 20 deaths.