Here is the full list of all 21 Before the Echo achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Discover the name of she who controls fate.
See the hidden ending.
Learn all spells.
Defeat an enemy on the seventh floor using only Arclight.
Defeat an enemy using only poison spells.
Trigger Boost a Trigger Boost.
Defeat an enemy with less than one second remaining on the clock.
Defeat an enemy within eleven seconds.
While learning a spell, achieve 100% accuracy for the entire song.
Synthesize every recipe in the game.
Synthesize Iridium.
Beat the game on any difficulty.
Obtain every droppable item in the game at least once.
Successfully complete a synthesis at 25% odds of success or lower.
Get her back.
Recover over 150 mana in a single battle, and win.
Queue up five spells in a row.
Complete a battle without failing a spell.
Obtain all three droppable items from any single enemy.
Defeat the Holiday Whompa.
Successfully defeat your first enemy.