Wonderful! First Macbeth, then Hamlet briefly, making a comeback? (5)
I believe the answer is:
magic
'wonderful' is the definition.
(I've seen this before)
'first macbeth then hamlet briefly making a comeback?' is the wordplay.
'first macbeth' becomes 'm' (1st letter of 'macbeth').
'then' means one lot of letters go next to another.
'hamlet' becomes 'cigar' (Hamlet is a brand of cigar).
'briefly' means to remove the last letter.
'making a comeback?' is a reversal indicator.
'cigar' with its last letter removed is 'ciga'.
'ciga' in reverse letter order is 'agic'.
'm'+'agic'='MAGIC'
(Other definitions for magic that I've seen before include "Tricks" , "Wonderful" , "Entertainment at a children's party?" , "'Charms, spells, illusions (5)'" , "Brilliant -- deception" .)