The 2nd Senalux Level Pack adds another 72 levels to the game. It also introduces rotation-locked hexes which can only be moved but not rotated. Additionally, it contains 5 new optical components:
the Diode lets light only pass from one direction
the Triangular Mirror reflects light from three sides
the Round Splitter cuts a beam in half and reflects it back
the Rotating Color Filter blocks colors based on its orientation
the Color Changer swaps Blue with Green with Red with Blue