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.
Discover the name of she who controls fate.
Synthesize every recipe in the game.
Defeat an enemy on the seventh floor using only Arclight.
Defeat an enemy using only poison spells.
See the hidden ending.
Synthesize Iridium.
Beat the game on any difficulty.
Obtain every droppable item in the game at least once.
While learning a spell, achieve 100% accuracy for the entire song.
Trigger Boost a Trigger Boost.
Defeat an enemy within eleven seconds.
Get her back.
Queue up five spells in a row.
Defeat an enemy with less than one second remaining on the clock.
Recover over 150 mana in a single battle, and win.
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.