Modern WarFare 2 is a First-person shooter game. It also has the capability to allow its user to interact online multiplayer as well. Modern Warfare 2 takes place in, of course, modern times. The plot to the main campaign takes place in the Middle-Eastthe power struggle there.
Op-For 
Spetnaz (Ultranationalists) 
U.S-Rangers 
British Task Force 141. Players cannot choose which faction to be it is random when each match begins.
A player can choose to go to multiplayer (online) from the main menu option. When the player logs in with their user name and password they will given an account that will keep up with a number of the player's records such as accuracy, kills, death, matches won and loss.
There a number of matches that a player can choose from.
Along with all this players can obtain weapons by gaining experience by completing challenges and game objectives. The higher level you get the more is unlocked. Players can also obtain titles and emblems for acheivments pre-determined by the designers. Also once a player has reach the highes level, 70, they have a choice to prestige. Prestiging is the option of a player to restart all challeneges and weapons gained to gain a higher level permanent emblem next to the player's In Game Name (IGN).