Here is the full list of all 15 Decarnation achievements.
Complete Act One.
Complete Act Two.
Complete Act Three.
Complete Act Four.
Complete Act Five.
Complete the game.
Make a fourth chess piece fall.
Win five games against the Magician.
Enter the museum without paying.
In the night club, obtain 5 stars on each song.
In the night club, win a game of hide and seek with a score of 3-0 in each location.
In the night club, defeat the Princess in combat at every difficulty level.
In the night club, make peace with Grolia.
Say goodbye to everyone in the night club before leaving.
Collect all the stars on your way to the South.