Here is the full list of all 28 Reflection of Mine achievements.
Find all the keys in the forest
Beat all stages in chapter one with perfect score
Defeat first boss
Destroy the Forest one
Beat first difficult stage
End tutorial
Defeat second boss
Find all the keys in the hotel
Destroy the Ugly one
Beat all stages in chapter two with perfect score
Someone is hidding in the hotel
Beat all stages in chapter one on neurosis difficulty
Beat all stages in chapter two on neurosis difficulty
Defeat third boss
Find all the keys in the church
Beat all the stages in chapter three with perfect score
Beat all stages in chapter three on neurosis difficulty
Destroy the saint one
Defeat fourth boss
Find all the keys in the asylum
Beat all stages in chapter four with perfect score
Beat all stages in chapter four on neurosis difficulty
Escape from asylum
Answer "yes" to the Dead One
Beat the game without collecting keys in chapter 1, 2 or 3
Beat the game
Beat the game on neurosis difficulty
Get 100% score