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