Since sometime in the early 1990s, two words have entered American English vocabulary that are frequently heard and read in the media, as noted in the Oxford English Dictionary Online, namely:
game-changer n. orig. U.S. (a) Sport a player who, or tactic, goal, etc., which decisively affects the outcome of a game; (b) (in extended use) an event, idea, or procedure that produces a significant shift in the current way of thinking about or doing something.
game-changing adj. orig. U.S. (a) Sport that decisively affects the outcome of a game; (b) (in extended use) that produces a significant shift in the current way of doing or thinking about something.
Now, there is nothing out of the ordinary about these two words in their meaning as applied to sports, but the “extended use” warrants commentary because it betrays yet again the mentality of speakers of American English in particular, derived in large part from the general English heritage of an attitude that regards everything as either “a show” or “a game.” Sentences like “Let’s get the show on the road” or “Who’s running the show?,” when no stage performance is literally involved and the application of the word show is in a purely transferred sense, is a special feature of English, hence not to be encountered in other languages. The same transference applies to game, whereby everything is capable of being likened to play-acting or artifice. Note, interestingly, that play and show are part of the same semantic universe, denoting as they do some variety of staged event for entertainment that is more properly to be observed in a theater, a stadium, or an arena than in real life.