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