Here is the full list of all 41 Pentiment achievements.
Finished Act 3.
Cut enough cookies for everyone at the Christmas feast.
Learn the mystery of the cats.
Get assistance climbing down the mine shaft.
Learn about Artemis and Apollo's frog plan.
Finished Act 2.
Get Guy killed.
Do your penance.
Lose everything at Lansquenet.
Get Aedoc his medicine.
Examine 10 flowers.
Discover the imposter.
Pass 5 dialogue checks.
Convince Endris to find his sweetheart.
Finished Act 1.
End Act I out of the abbot's favor.
Get Ferenc executed.
Tell Jacob Estler immaterial gossip.
Have your hat stolen.
Spin wool as fast as the ladies.
Encourage Paul to draw.
Get Wojslav to let you into the cellar.
Solve Ferenc's cipher with the volvelle.
Pet 5 animals.
Convince Illuminata to give you the French book.
Find the secret door to library.
Get Lucky executed.
Get Matilda executed.
Get Ottilia executed.
Get Martin killed.
Get Hanna killed.
Headbutt Werner.
Seduce Zdena.
End Act I in the abbot's favor.
Convince Gernot to let you dig up the grave.
Convince Jacob Estler to save Ottilia's home.
Get knocked out.
Win everyone's money at Lansquenet.
Complain to Niko about your room.
Shoot the deer.
Refuse to shoot at the deer.