Same, it took almost til the end for me! At first I was rebus-ing ZERO into all the Z boxes, but it still wasn't quite adding up until I looked at the rest of the acrosses and saw that ERO was already there! Very fun and well-executed.
The joke was supposed to be that sneakerheads (folks into collecting sneakers) are into "gazing at shoes", hence they'd be into SHOEGAZE16DRock genre for sneakerheads?[--------]