Notice about game being shortened (8)
I believe the answer is:
abridged
'being shortened' is the definition.
('abridged' can be similar in meaning to 'shortened')
'notice about game' is the wordplay.
'notice' becomes 'ad'.
'about' means one lot of letters goes inside another.
'game' becomes 'bridge' (bridge is a kind of game).
'ad' enclosing 'bridge' is 'ABRIDGED'.
(Other definitions for abridged that I've seen before include "Epitomised" , "Shorter" , "Cut short - big adder (anag)" , "Shortened as book may be" , "Abbreviated, contracted" .)