Complex sentence: Fred and Velma face the Phantom, who sings the whole way through Stage 1 of the fight, where Velma must hack two controls to shut off the lights and coax the Phantom off of his perch.
Split into simpler sentences: Fred and Velma face the Phantom, who sings through the whole first portion of the fight. In Stage 1 of the fight, where Velma must hack two controls to shut off the lights and coax the Phantom off of his perch.