"Call of Duty 4: Modern Warfare will introduce a variety of game play styles into the single player campaign completely new to the Call of Duty series. The game moves away from the standard three country-specific campaign style, and allows the plot the play through more like a film style plot with interlaced story lines from the perspective of the player as a member of the US Force Recon, British S.A.S. and a variety of cameo-style missions where you will play one mission as various other soldiers such as an AC-130 Specter Gunship gunner, or as one part of a two man sniper team behind enemies line in a flashback style mission.
Call of Duty 4: Modern Warfare will focus on the variation of Modern warfare as an infantry soldier by allowing the player to control soldiers in a vast amount of different scenarios, straying away from the constant "at eleven" action of previous Call of Duty titles and allowing for both heavy intensity fire fights and slower paced drama styled intensity. The developer, Infinity Ward, has so far shown off a handful of such levels including where the user will play as the gunner of an AC-130 Gunship, the pilot of a Cobra Helicopter providing air support, a marksman part of a two man sniper team, a Marine in the US Force Recon, and a special operations soldier in the British S.A.S..
The series move to Modern warfare has also introduced a variety of new modern weapons and technology to be introduced to the Call of Duty franchise. Such showcased weapons and attachments include M203 Grenade Launchers, IR Laser Pointers for use in conjunction with night vision goggles, silenced MP5SD submachine guns, and the FGM-148 Javelin man-portable anti-tank guided missile among many others." - [url=http://en.wikipedia.org/wiki/Call_of_Duty_4:_Modern_Warfare:b4ad1]Source[/url:b4ad1]