Retrospectively criticises game (4)
I believe the answer is:
snap
'game' is the definition.
(card game)
'retrospectively criticises' is the wordplay.
'retrospectively' shows that the letters should be reversed in order.
'criticises' becomes 'pans' (pan can mean to criticise severely).
'pans' reversed gives 'SNAP'.
(Other definitions for snap that I've seen before include "Speak irritably; photo" , "Become unhinged" , "A walk in the park < to shoot" , "Simple card-game" , "Unpremeditated - bite" .)