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