A ‘game over’ is when you can’t continue the game as you were. For some games, this is because you’ve lost lives and don’t have extras, your HP went to 0, or some other criteria such as an objective left undone. Players have to load a saved game, load from a checkpoint, or start again to continue the game. Some other games have started playing around with this mechanic and allows you to continue playing but with added difficulties or the game over screen means to fake out the player. Mostly used in single-player games.