Here is the full list of all 12 Signal to Noise achievements.
Kill two bosses in one song.
Kill 7 enemies with one laser.
Break 3 powerup spheres by flying into them in one song.
Get 1000000 points.
Get 100000 points.
Avoid taking damage for 30 seconds.
Get 10000 points.
Finish a song with 20% health or less.
Complete a song without dying.
Get 10000000 points.
Get 100000000 points.
Catch 20 health in a row without letting one pass by.