Here is the full list of all 15 DRAGON: A Game About a Dragon achievements.
Clear the game without increasing your HP from taking damage.
Finish the game with the regular ending.
Finish the game with the best ending.
Complete the NPC's secret sidequest.
Get Dragon to whistle three particular songs.
Find the Stannum Sollerets and all five gemstones.
Learn to use Magic Breath.
Find five very special treasures.
Defeat the king's bodyguards without taking damage.
Trick a Lancer into dashing down a pit.
Defeat the Admiral without taking damage.
Defeat the Bishounent without taking damage.
Have 10,000 gold at once without depositing it at home.
Defeat Boudouin and Alex without taking damage.
Defeat TM-061 without taking damage.