Non-missable story achievement which pops at the very end of Act III. This chapter is very combat intensive so do your best to avoid fights and preserve ammo/health. The trickiest part of the act is the two light puzzles halfway through the level.
1st Light Puzzle Solution:Point the middle circle’s bar toward the right-hand circle to disconnect the top two circles from each other.
Turn the left circle until it lights up.
Point the middle circle's bar towards the left-hand circle this time.
Turn the right circle until it lights up.
Point the middle circle's bar back towards the right-hand circle.
Turn the right circle four times.
Point the middle circle's bar back towards the left-hand circle.
Turn the right-hand circle until it lights up again.
Point the middle circle's bar towards the bottom circle.
2nd Light Puzzle Solution:Point the bottom-middle circle’s bar towards the top-middle circle to disconnect the left and right circles from each other.
Turn the left circle until it lights up.
Turn the top-middle circle until it and the highest middle circle lights up.
Point the bottom-middle circle's bar towards the right-hand circle this time.
Turn the right circle five times.
Point the bottom-middle circle's bar towards the top-middle circle gain to disconnect the left and right circles.
Turn the right circle until it lights up.
Point the bottom-middle circle's bar towards the bottom circle.
Video guide for the full Act and fastest completion method/puzzle solutions: