Here is the full list of all 19 Curse of the Crescent Isle DX achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Complete a stage without taking damage
"Accidentally" kill an enemy
Collect all 27 coins in the game
Talk to the statue in the town
Hit the third boss three times on its way up
Complete the game as the King
Complete the game as the Queen
Complete a stage in co-op
Complete the game with no coins
Jump off an enemy while grabbing him
Complete the Boss Rush Mode
Complete Speed Run Mode
Take damage by staying underwater too long
Defeat Grondor of the Forgotten Mine
Defeat Naja Naja
Defeat Aranomanom
Let a Carfee fall in the water
Find one of the special messages in the password screen
Break one of those big rocks