The corny fools at ESPN - and their brain dead followers - now use the term to decribe virtually any play that ends the game; walk-off hit, balk, double, single, etc.
"Game-ending" and "Game-winning" have surrendered.
Dude, remember that girl that we saw last night that looked like Katie Perry? Well, I totally jacked a Walk Off Home Run on her last night! She won't be forgetting me anytime soon.