There are two main things that set Team Fortress 2 apart from other major first-person-shooters on the market: its refined art style inspired by J.C. Leyendecker, and the variety of the nine classes that form a team. In games like Call of Duty: Modern Warfare 3 and Battlefield 3, selecting a class offers as much variety as weapon type (which includes all standard military-grade weaponry) and perks (which can be customized and homogenized). In Team Fortress 2, class choices go beyond this and offer completely different play-styles, utilities, roles and a tight dynamic relationship between other classes that work towards building a game where team work is not just recommended, but required.