Genre

The subject of genre is a broad and wide subject that applies to many different things in a game, unlike most things in the game industry though it affects the very core of a game, the very essence of a game is what genre it is.

The base meaning of genre is what kind of game it is in the first place, is the game something that will shock you and have you jumping out of your chair? or is it a run and gun shooter where if something moves in the game the first thing you think to do is shot it.
Genre also affects the environment and general setting of the game, it may be in a lush jungle or a barren wasteland, but in some cases a game includes a bit of everything in a game and that too is a genre all on it's own on a whole other level, and is yet another example of  how broad the subject of genre is and will continue to get.