Campaign
The player assumes the role of various characters during the single-player campaign, changing perspectives throughout the progression of the story. Each level is a mission that features a series of objectives that are displayed on the heads up display, which marks the direction and distance towards and from such objectives. Damage to the player is shown by blood shown on the screen. The player's health regenerates as time passes. Tasks vary in their requirements, having the player arrive at a particular checkpoint, eliminate enemies in a specified location, stand their ground to defend an objective, or plant explosive charges on an enemy installation. The player will be accompanied by troops who cannot be issued orders.
Cooperative
Infinity Ward and Sledgehammer Games have revealed that Modern Warfare 3 will feature a new Survival Mode. Survival Mode features one to two players fighting endless waves of enemies with each wave getting more difficult. Despite being much compared to the World at War Nazi Zombies mode, enemies do not spawn at fixed locations like the zombies do, but instead, at tactical positions based on the current location of the player. The mode will be available on all multiplayer maps in the game and in the mode, players can earn "cash" for items such as weapons, upgrades and ammo.
Multiplayer
Infinity Ward and Sledgehammer Games have also recently revealed that they have revamped the entire killstreak reward system. They have stated that while Treyarch had slightly improved the system, it was not enough to make the system feel perfect. There are now 3 different "strike packages" for killstreaks called Assault, Support, and Specialist. The Assault strike package works the same as the default killstreak reward system in Modern Warfare 2 and Black Ops offering killstreaks like the predator drone and helicopters. The Support strike package offers support-style rewards such as UAVs and SAM Turrets. Unlike previous games in the franchise, the Support strike package will not make the player's killstreak reward reset upon death, but instead, accumulate over the course of a match. The Specialist strike package rewards players with perks instead of killstreaks. After every eighth consecutive kill, the player will receive every perk in the game, but will reset back to none upon death.
Along with revamping the entire killstreak reward system, Modern Warfare 3 will also have a completely revamped ranking and unlocks system. Unlike Call of Duty: Black Ops, Modern Warfare 3 will not use a currency system.Infinity Ward and Sledgehammer Games have also revealed that they are removing annoyances that make players rely less on skill and more on perks. To do this, they are removing certain perks that give players a power advantage over others who do not possess the same perk. 'Quick-scoping' has also returned, having been absent in Black Ops.Unlike Black Ops, Modern Warfare 3 will not feature dive to prone or "dolphin dive" due to various balancing issues.The teams have also revealed that to fix bugs and glitches, they will not use full updates but instead Treyarch's hot fix system to fix problems much quicker.
A new gamemode has also been added titled "Kill Confirmed." Kill Confirmed requires players to collect floating dog tags from the corpse of a downed enemy before the kill can be registered. However, the opposing team can pick up the dogtag aswell to deny the other team of a kill. Another gamemode has also been added titled "Team Defender". In Team Defender, each team must cap the opposing team's flag, and hold it to accumulate points. Private matches also now include pre-made gamemodes including "Infection" (where the infected kills enemies to recruit them to their team), "Drop Zone" (where you must hold a drop zone for points and care packages), "Team Juggernaut" (each team plays alongside an AI Juggernaut character), "Gun Game" (be the first to get one kill with every gun in the game) and "One In The Chamber" (in which players are only allowed one pistol with one bullet and three lives where they can only get more bullets by killing other players). Along with this, players are allowed to create there own gamemodes with there own customized rules such as amount of player and time limit.
