Here is the full list of all 42 Lies of P achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
[Free from the puppet string] Reach the ending.
Find out about the last story of Sophia.
Collect all special weapons.
[Rise of P] Reach the ending.
Kill the Nameless Puppet.
Collect and play all records.
Collect all Legion Arms.
Collect all normal weapons.
Play a perfect tune on the piano at Hotel Krat.
Find out about the last story of Geppetto.
[Real boy: They all lived happily ever after] Reach the ending.
Find out about the last story of Simon Manus.
Kill the Awakened God Simon Manus.
Learn all gestures.
Find out about the last story of Venigni.
Discover all Trinity Sanctums.
Decipher all cryptic vessels and claim the rewards.
Kill Laxasia the Complete.
Find out about the last story of Antonia.
Strengthen a special weapon to its max level.
Find out about the last story of Eugénie.
Kill the Black Rabbit Brotherhood.
Activate P-Organ to Phase 5.
Strengthen a normal weapon to its max level.
Kill the Corrupted Parade Master.
Modify a Legion Arm to its max level.
Kill the Puppet-Devouring Green Monster.
Kill Champion Victor.
Kill all types of Dimensional Butterflies.
Kill Romeo, King of Puppets.
Harvest Gold Coin Fruit.
Kill the Eldest of the Black Rabbit Brotherhood.
Kill the Fallen Archbishop Andreus.
Kill King’s Flame, Fuoco.
Try to assemble a weapon.
Kill the Scrapped Watchman.
Kill a Stalker.
Tell a lie in front of Hotel Krat Entrance.
Kill the Parade Master.
Repair a Stargazer.
Deliver a successful Fatal Attack.
Destroy an enemy’s weapon with a perfect guard.