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.
Get Martin killed.
Get Hanna killed.
Do your penance.
Refuse to shoot at the deer.
Shoot the deer.
Discover the imposter.
Get knocked out.
Lose everything at Lansquenet.
Win everyone's money at Lansquenet.
Get Aedoc his medicine.
Examine 10 flowers.
Complain to Niko about your room.
Finished Act 1.
End Act I out of the abbot's favor.
Get Ferenc executed.
Convince Jacob Estler to save Ottilia's home.
Tell Jacob Estler immaterial gossip.
Get Matilda executed.
Get Ottilia executed.
Pass 5 dialogue checks.
Have your hat stolen.
Get Wojslav to let you into the cellar.
Seduce Zdena.
Pet 5 animals.
Headbutt Werner.
Solve Ferenc's cipher with the volvelle.
Convince Illuminata to give you the French book.
Find the secret door to library.
Encourage Paul to draw.
Get Lucky executed.
Spin wool as fast as the ladies.
End Act I in the abbot's favor.
Convince Gernot to let you dig up the grave.
Convince Endris to find his sweetheart.