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