Hard case ruined game (8)
I believe the answer is:
charades
'game' is the definition.
(charades is a kind of game)
'hard case ruined' is the wordplay.
'ruined' is an anagram indicator.
'hard'+'case'='hardcase'
'hardcase' with letters rearranged gives 'CHARADES'.
(Other definitions for charades that I've seen before include "Miming parlour game" , "Games like this" , "Game in which answers are acted out" , "Party guessing game" , "Guessing game where words are acted out" .)