Here is the full list of all 12 Lucidity achievements.
Complete all Bonus Levels
Act III completed
Act II completed
Collected 1500 fireflies
Beat 'All Around is Petrified' without taking any damage
Collected 1000 fireflies
Beat 'Deep Sleep Dive' without collecting any fireflies
Collected 500 fireflies
Collect all the fireflies in 'Every Kite Soars' in a single run
Act I completed
Collected 100 Fireflies
First Level Completed