game-changer

game-chang·er

or game changer  (gām′chān′jər)
n.
An idea or event that significantly changes the way something is done or thought about: "A few years ago, New York baker Jim Lahey gave us a method for no-knead artisan loaves.... Calling for much less hands-on work than other recipes, it was a game-changer in the world of bread baking" (Amanda Gold).