The ultimate feature of some games (5)
I believe the answer is:
Here is my best explanation:
'the ultimate feature' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'of some games' is the wordplay.
'of' indicates a hidden word.
'OMEGA' can be found hidden inside 'some games'.