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 Eugénie.
Collect and play all records.
Find out about the last story of Geppetto.
[Real boy: They all lived happily ever after] Reach the ending.
Learn all gestures.
Collect all special weapons.
Find out about the last story of Venigni.
Collect all normal weapons.
Find out about the last story of Antonia.
Decipher all cryptic vessels and claim the rewards.
Find out about the last story of Sophia.
Play a perfect tune on the piano at Hotel Krat.
Collect all Legion Arms.
[Rise of P] Reach the ending.
Kill the Nameless Puppet.
Find out about the last story of Simon Manus.
Kill the Awakened God Simon Manus.
Kill Laxasia the Complete.
Activate P-Organ to Phase 5.
Discover all Trinity Sanctums.
Strengthen a special weapon to its max level.
Kill the Black Rabbit Brotherhood.
Strengthen a normal weapon to its max level.
Modify a Legion Arm to its max level.
Kill the Corrupted Parade Master.
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.
Kill the Scrapped Watchman.
Destroy an enemy’s weapon with a perfect guard.
Try to assemble a weapon.
Kill a Stalker.
Tell a lie in front of Hotel Krat Entrance.
Kill the Parade Master.
Repair a Stargazer.
Deliver a successful Fatal Attack.