Here is the full list of all 19 BIT.TRIP FLUX achievements.
Escaped Nether Mode
Get a PERFECT score in Epiphany
Get a PERFECT score in Perception
Get a PERFECT score in Catharsis
Beat the game on Normal difficulty
Chained 100 Beats
Chained 200 Beats
Chained 500 Beats
Watch the hidden cutscene
Beat Epiphany in Normal difficulty
Beat Perception in Normal difficulty
Beat Catharsis in Normal difficulty
Beat the game, from start to finish, in one sitting
Register a high score on the leaderboards
Block all Beats during a Subtract Challenge
Block 10,000 Beats
Enter Meta Mode in each level
Achieved a multiplier of 50 in Normal difficulty
Achieved a multiplier of 100 in Normal difficulty