Developer Infinity Ward decided before to involve the Call of Duty community in making one of the biggest decisions for Call of Duty 4: Modern Warfare ... the box art.
Their art department created five different box art concepts to choose from (Alpha, Bravo, Charlie, Delta, and Echo)
And now, after gathering all the feedback and tweaking the designs, Infinity Ward ended up with the final design people have chosen. The winning design is based off of the "Charlie" concept blended with a touch of "Echo" for good measure.
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 portable anti-tank guided missile among many others.
A Russian nationalist by the name of Zakhaev is set on returning his homeland to the Soviet times. Zakhaev knows the United States would never allow this to happen, thus he funds a coup in the Middle East, organized by his ally Al-Asad, to draw attention away from Russia. The two men and their seconds-in-command gain the nickname The Four Horsemen. However, the British and US governments have been monitoring Zakhaev's activities and discover his real intentions. The story is told from a perspective of a British 22nd SAS Regiment operative in Russia and American 1st Force Recon in the Middle East.
For Multiplayer, it has been confirmed that Call of Duty 4 will include a class system which has five preset classes with default weapon load outs and perks assigned to them as well as allows users to create five custom classes where the user can customize their weapon load out and three perks to assign to their soldier. The five default classes include Assault, Spec Ops, Light Machine Gunner, Demolitions, and Sniper class. Create a class will be unlocked when the user gains enough Experience Points (XP), earned by killing his/her opponent, and becomes a Private (level 4), and will increase rank with more XP earned. XP will also vary depending on the type of match the user is playing. Only two of the classes are available to a first time player; the rest are unlocked as he gains more experience online and gains higher rank.