In COD4 you play as 3 main characters, depending on the mission and where and ever what year you will be that character. You switch between Missions as either S.A.S or U.S.M.C.

This Game has great graphics and uses the enviorment extremely well, depending on where you decide to take cover depends on if you live or die, and trust me most the time you go behind a car that just may explode on you when you least expect it.  All in all COD 4 made me very very happy and I cant stop playing. And on my classic 1-10 scale  COD4 gets a 10