Here is the full list of all 32 Curse of the Assassin achievements.
Complete the gamebook in Classic Mode
Roll 3 sixes in one roll
Roll 3 ones in one dice roll
Find the best weapon in the gamebook
Meet a Sanziana and receive a special gift
Discover a dastardly plot
Laugh hysterically with Esplandian
Steal a sheep
Receive a threatening letter
Learn the secrets of Coyote Lore
Complete the gamebook in Adventurer Mode
Find all the artwork in Curse of the Assassin
Become possessed by an ultimate boss
Find out the meaning behind the 'breadbasket of Orlandes'
Complete the gamebook in Casual Mode
Recruit all members of the Death Hawks
Return a cry three times when out at sea
Successfully report back to the Head Gaoler
Meet all the creatures from folklore and legend
Fool the mighty Coca Rabixa
Return a ring to the rightful owners
Receive a special blessing
Find out the location of the Jewel of Orlandes
Defeat the leader of the Hombre Peces
Find the best armour in the gamebook
Visit all the taverns in the story
Successfully use your hunting skills
Save a companion from some watery rapids
Offer your life for another
Hear the 'Endecha de la Sangre'
Rescue two people very close to you
Purify the water in a well