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.
Collected all the "Dream Album" files.
Found all hidden items in Somnium.
Found 6 hidden items in Somnium.
Confronted So with the evidence with no mistakes.
Admired the Sagan's stereo equipment.
X-rayed the Mermaid.
Saw three autographs of crazy customers in Somnium.
Almost got cursed by Adorabbit in Somnium.
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.
Saw This Man twice in Somnium.
Day 4: Monday - Cleared #89's Somnium.
Had Aiba wear the basket and the pot in Somnium.
Finished Ota's investigation.
Day 5: Tuesday - Cleared Mayumi's Somnium.
Confronted Ota with the evidence with no mistakes.
Finished Mizuki's investigation.
Day 6: Wednesday - Cleared Date's Somnium.
Cleared the shooting event at the Sejima residence with no misses.
Collected 100 "Appendix" files.
Asked out the receptionist to Atami.
Day 4: Monday - Cleared Ota's Somnium.
Day 3: Sunday - Cleared Iris's Somnium.
Confronted Iris with the evidence with no mistakes.
Cleared the shooting event at the Kumakura office with no misses.
Enjoyed a fulfilling chat with Kagami.
Checked absolutely everything in Boss's office.
Finished Iris's investigation.
Day 5: Tuesday - Cleared Iris's Somnium.
Cleared the shooting event at the Warehouse District with no misses.
Day 4: Monday - Cleared Iris's Somnium.
Cleared the shooting event at Golden Yokocho with no misses.
Day 3: Sunday - Cleared So's Somnium.
Day 2: Saturday - Cleared Mizuki's Somnium.
Day 1: Friday - Cleared Date's Somnium.
Found 1 hidden item in Somnium.