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