Call of Duty: Modern Warfare 2 is a first-person shooter video game developed by Infinity Ward and published by Activision for the Xbox 360 and PlayStation 3 video game consoles and the Microsoft Windows operating systems. Officially announced on February 11, 2009, the game was released worldwide on November 10, 2009. It is the sixth installment of the Call of Duty series and the direct sequel to Call of Duty 4: Modern Warfare, continuing along the same storyline. It was released in conjunction with two other Call of Duty games: Call of Duty: Modern Warfare: Mobilized for the Nintendo DS, and Call of Duty: Modern Warfare: Reflex, a port of Call of Duty 4 adapted by Treyarch for the Wii console. In addition, a comic book series based on one of the game's characters was also produced, entitled Modern Warfare 2: Ghost.
Modern Warfare 2 has received highly positive reviews from various gaming websites, attaining a 94% aggregate score on Metacritic, with praise stemming primarily from its in-depth multiplayer component. Upon its release, the game sold approximately 4.7 million copies worldwide in 24 hours. On June 15, 2010, Activision confirmed that the game had sold over 20 million copies worldwide, making it the second best-selling game of all time in the UK, and the third best-selling game of all time in the US.
The online multiplayer mode of Modern Warfare 2 retains the same experience points and unlockable reward system as that of Call of Duty 4, with game modes that include Free-For-All, Search & Destroy, Demolition, Sabotage, Domination, Team Deathmatch, and Capture The Flag. Modern Warfare 2 introduces several new features. Aside from new weapons, equipment, and perks that upgrade to "pro versions" after meeting utilization requirements, fifteen different kill streak rewards can be unlocked and selected by the player. Among these is the ability to receive a supply drop after achieving four kills in a row, order a Predator missile strike after five kills, and call in an AC-130 gunship after eleven kills. Players can also gain a tactical nuke if they obtain a 25 kill streak. The nuke will blow up the whole map and achieve victory in a match for the player or team that called in the nuke regardless of whether the team was winning or losing at the time the nuke was called in. Another new feature is the in-game host migration; if a match host leaves the game, or if the host struggles to support the game, a 'host migration delay' allows a new host to be selected and the game to continue. There is also the addition of an optional third person mode which can be used in certain game types.
Gameplay in the online multiplayer mode. The weapon pictured has the heartbeat sensor attachment, a new feature included in Modern Warfare 2.In the Xbox 360 version of the game, the party chat system is disabled while the player is playing online in certain playlist types. This decision, designed to promote cooperation amongst team members, has caused some controversy within the Xbox Live community. The offline (splitscreen and LAN) multiplayer mode retains the experience and rewards system found online, a first for the series since the system was introduced. However, the rewards are separate from those that are earned while playing online.
For the PC version, Infinity Ward decided to implement a new matchmaking service: IWNET working through Steam. This system is nearly identical to the console version of IWNET. Dedicated server support is removed, eliminating the ability for mods or user-created maps to be incorporated. This removal has created anger among many PC gamers. Since the multiplayer aspect runs within Steamworks, the PunkBuster anti-cheat system utilized in previous titles has been replaced by Valve Anti-Cheat. In addition, the PC version shares the same 18-player cap as the console versions (matches are a maximum of 9 versus 9).