Here is the full list of all 45 AI: The Somnium Files achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Obtained all other trophies.
X-rayed the Mermaid.
Almost got cursed by Adorabbit in Somnium.
Admired the Sagan's stereo equipment.
Saw This Man twice in Somnium.
Confronted Iris with the evidence with no mistakes.
Confronted Ota with the evidence with no mistakes.
Confronted So with the evidence with no mistakes.
Found all hidden items in Somnium.
Collected all the "Dream Album" files.
Checked absolutely everything in Boss's office.
Cleared the shooting event at the Kumakura office with no misses.
Found 6 hidden items in Somnium.
Asked out the receptionist to Atami.
Finished the final investigation.
Discovered the marriage of the yakuza and the nurse.
Kept your cool and did not shoot Saito.
Collected all the "Persons" files.
Day 6: Wednesday - Cleared Saito's Somnium.
Finished Annihilation Route investigation.
Day 5: Tuesday - Cleared Boss's Somnium.
Cleared the shooting event at the Sagan residence with no misses.
Day 5: Tuesday - Cleared Hitomi's Somnium.
Confronted Hitomi with the evidence with no mistakes.
Finished Iris's investigation.
Day 5: Tuesday - Cleared Iris's Somnium.
Cleared the shooting event at the Warehouse District with no misses.
Collected 100 "Appendix" files.
Day 4: Monday - Cleared Iris's Somnium.
Cleared the shooting event at Golden Yokocho with no misses.
Day 3: Sunday - Cleared So's Somnium.
Found 1 hidden item in Somnium.
Finished Ota's investigation.
Day 5: Tuesday - Cleared Mayumi's Somnium.
Had Aiba wear the basket and the pot in Somnium.
Saw three autographs of crazy customers in Somnium.
Day 4: Monday - Cleared #89's Somnium.
Finished Mizuki's investigation.
Day 6: Wednesday - Cleared Date's Somnium.
Cleared the shooting event at the Sejima residence with no misses.
Day 4: Monday - Cleared Ota's Somnium.
Day 3: Sunday - Cleared Iris's Somnium.
Enjoyed a fulfilling chat with Kagami.
Day 2: Saturday - Cleared Mizuki's Somnium.
Day 1: Friday - Cleared Date's Somnium.