Here is the full list of all 14 Melatonin achievements.
Get all perfect scores
Collect all rings in the game
Finish a custom edited level
Get through the morning
Collect all stars in the game
Get through night 4
Get through night 3
Score 3 rings in a level
Get a perfect score in hard mode
Get a perfect score in scored mode
Score 3 stars in a level
Perfect the tutorial
Get through night 2
Get through night 1