Video games come in many different shapes and sizes, but usually, players can get some idea of what to expect from any individual game. If the game is part of a series, it will likely become known for certain aspects, whether it is story, characters, gameplay, themes, or aesthetic choices. It might feel weird, for instance, to play a Call of Duty campaign centered on diplomacy or a Tomb Raider game that is not about Lara Croft. There can be exceptions, but those are usually clearly marked. One doesn't typically start a Mario game expecting to play a gritty first-person shooter. But as much as games contain patterns, the developers often like to add variety to the experience.