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