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