"Game Change" is, of course, about the game changing. Nikita Season 2 is vastly different than Nikita Season 1. Nikita and Michael are together, holding a black box and trying to take down Division. Alex, on the other hand, is also out of Division but is helping them retrieve the black box in exchange for help taking down the people who killed her father. Gone are the days when Alex was the innocent girl who was actually spying for Nikita. Gone are the days when Michael chased after Nikita.
The plot isn't to interesting--Nikita and Michael helping a guy framed for murdering and exposing one of Division's coverups--but the episode ends with a lasting, brutal scene. Facing down against Alex, Nikita kicks her ass, proceeds to break her arm and shoots her in the leg, all while Alex wails. It doesn't get more serious than that.