Hardcase developed game (8)
I believe the answer is:
charades
'game' is the definition.
(I know that charades is a type of guessing game)
'hardcase developed' is the wordplay.
'developed' indicates an anagram.
'hardcase' with letters rearranged gives 'CHARADES'.
(Other definitions for charades that I've seen before include "Games like this" , "Party guessing game" , "Miming games" , "Guessing game where words are acted out" , "Miming parlour game" .)