Here is the full list of all 23 LIT: Bend the Light achievements.
See the devs
Find as many solutions as the devs planned
Find all solutions the devs planned and at least one more
Solve a previously skipped level
Solve all levels
Accumulate 1000 light beam bounces across all your solutions
Solve Level 27 with more than 2 bounces
Find 75% off all solutions
Solve level 9 by hitting all the movable objects
Listen to the menu music for 10 minutes
Find 50% of all solutions
Accumulate 500 light beam bounces across all your solutions
Solve level 12 using one of the mirrors twice
Solve level 12 using only one mirror
Solve level 11 letting the light bounce at least 25 times
Solve level 11 not using the mirrors counterclockwise and without skipping any
Find 25% aff all solutions
Find more solutions than the devs in at least one level
Solve level 6 using 2 or less mirrors
Find all solutions for a level with at least 3 possible solutions
Accumulate 100 light beam bounces across all your solutions
Solve level 4 without using the side mirror.
Find an alternative solution for a level