Here is the full list of all 19 Blacksea Odyssey achievements.
Unlock by beating Elite Mode.
Unlocked by opening up 500 chests.
Unlock by beating the game in 60 minutes.
Unlock by killing every boss in the game.
Unlock by beating the game with a score of 500,000 or greater.
Unlock by completing the game.
Unlock by equipping three fire spear runes at once.
Unlock by equipping three lighting spear runes.
Unlock by killing Cthulhu.
Unlock by killing Charybdis
Unlock by collecting a bounty without taking damage.
Unlocked by completing the Bestiary.
Unlock by equipping three ice spear runes at once.
Unlock by equipping three poison spear runes at once.
Unlock by killing an enchanted boss.
Unlock by killing Leviathan.
Unlock by ripping off 100 enemy weak points.
Unlock by having 20 items at once.
Unlock by clearing all enemy zones in a level.