Here is the full list of all 13 Particles of Reality achievements.
Read all of Sebastian's endings in Obsession.
Read all of Julian's endings in Obsession.
Read all of Quinn's endings in Obsession.
Unlock all of Sebastian's CGs in Obsession.
Unlock all of Julian's CGs in Obsession.
Unlock all of Quinn's CGs in Obsession.
Read all 'Particles' Chapters
Read all of Sebastian's What If scenario endings.
Read all of Quinnn's endings in Obsession.
Read all of secret character's endings in Obsession.
Unlock all of Secret Character's CGs in Obsession.
Unlock all Endings, Chapters, CGs, and What If endings in Obsession