A pretty fancy Monday, with a fun theme, and the verticality is a welcome change. Some of the secondary fill is nice, too, like ALCATRAZ (30A: Former penitentiary in San Francisco Bay), PARMESAN (46A: Grated cheese), NUANCE (25A: Shade of meaning), SCOFFS (7A: Expresses derision), and others.
Fun clue for USHER (38A: One with a leading role?), nice crossing of 68A: Imbecile (ASS) and 48D: Imbeciles (IDIOTS), and I'll give extra credit for any puzzle offering a 17A: ____ and tonic (GIN).
There's a little crosswordese, sure, but it's a solid puzzle today. Also, when's the last time you thought of KALKAN (23D: Alpo alternative?).
Good way to start the week.