Here is the full list of all 36 Oceanhorn - there are Monster of Uncharted Seas achievements worth 1,000 gamerscore.
Smash 50 skeletons to pieces
Kill an enemy with a burning arrow
Reach the highest Adventurer Level
Collect Bloodstones from all over the world
Catch one fish of every kind
Kill 50 Spawn
Melt objects 15 times using Fire Spell
Get all 8 heart containers
Collect 10 Cursed Skulls
Beat the Creation No. 2
Swim to Canals
Defeat every kind of monster in the game
Visit all islands of Uncharted Seas
Spend 2000 coins in the shop
Clear the entrance to Grand Core
Kill an enemy with a laser beam
Study the Arcadian History
Collect 1000 coins
Break a crate with Trencher Boots
Ship an item to another island
Find out what happened to Honey Man
Kill an enemy by pushing a crate
Use bombs to break walls 10 times
Collect your first 25 coins
Protect the Peace in Tikarel
Bounce an enemy with a shield 10 times
Lift the curse from the Forest Shrine
Release the Direfolk's prisoner
Defeat the Cepedes of Abandoned Mines
Kill three enemies with a single sword blow
Move crates and other objects 100 times
Use your wits to reveal the hidden treasure
Perform 10 successful combo attacks
Find your first Piece of Heart
Get father's sword and shield
Read at least 10 signs