Everything in the show could be superficial (3)

I believe the answer is:

all

I'm a little stuck... Click here to teach me more about this clue!

'everything' is the definition.
(all things)

I don't understand the remainder of the clue.

(Other definitions for all that I've seen before include "Everyone - complete" , "and 16 Across and 23 Across: Even so" , "Garden passage between trees or bushes" , "Wholly" , "Completely, everything" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app