The most common and most likely answer to this crossword clue is the 8 letter word MOORCOCK
I've seen this crossword clue in The Guardian
M
O
O
R
C
O
C
K
More clues leading to the result MOORCOCK
Buddy explains!

The straight part
We know that "Game" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case game = moorcock.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MOORCOCK mean?
MOORCOCK noun- The red grouse.