Here is the full list of all 18 Olea's Descent achievements.
Who doesn't like to buy a pig in a poke?
Buy a book.
Ride the Elevator down the first time.
This one looks familiar. We are not liable for hurting fingers.
Have 50 Intellect without Item bonuses
Have 50 Strenght without Item Bonuses
Have 50 Agility without Item Bonuses
Have 50 Faith without Item Bonuses
Defeat the possessed roots of an old magical plant.
Defeat the last Boss on Depth 15
Disarm 50 Traps (All Characters)
Find all 15 Notes
Find all 3 common Pets
Find all 3 uncommon Pets
Find all 3 rare Pets
Find all 3 very rare Pets
Find the extraordinary Pet
Find all Pets included in the Chests