Call of Duty is a first-person shooter video game developed by Infinity Ward and published by Activision. The game simulates the infantry and combined arms warfare of World War II. The game is based on the Quake III: Team Arena engine. It was accompanied in September 2004 by an expansion pack, Call of Duty: United Offensive, which was produced by Activision, and developed by Gray Matter Interactive, with contributions from Pi Studios.

Call of Duty: United Offensive is an expansion pack for the popular first-person shooter computer game, Call of Duty. It is developed by Gray Matter Interactive, with contributions from Pi Studios, and published by Activision. It was released for Microsoft Windows on September 14, 2004. Since October 13, 2006, the game has also been available to buy on Valve's content delivery platform, Steam. This comes after an agreement with its publisher, Activision. Continuing from the original game, much of the American Campaign is influenced by Band of Brothers. The Sicily mission is arguably influenced by The Guns of Navarone.

Call of Duty 2 is a first-person shooter video game and sequel to the critically acclaimed game Call of Duty. It was developed by Infinity Ward and published by Activision. It was released on October 25, 2005 for PC and November 15, 2005 for the Xbox 360. Other versions were made for mobile phones as well as Pocket PCs and Smartphones. The game is set during World War II and is experienced through the perspectives of three soldiers in the Red Army, British Army and United States Army. The game was met with a positive public reception, receiving mostly positive reviews from critics. The Xbox 360 version sold over 250,000 copies in its first week, and had sold 1.4 million copies by October 2006.

Call of Duty 4: Modern Warfare is a first-person shooter video game developed by Infinity Ward and published by Activision for Xbox 360, PlayStation 3 and Windows. It is the fourth installment in the Call of Duty video game series, excluding expansions. It is also the first one to break away from the World War II setting and be set in modern times, and the first game in the series to be rated Mature in North America. The title and game details were announced on April 25, 2007. It was released worldwide between November 6, 2007 and November 9, 2007, and became available on Steam on November 6, 2007 for pre-purchase, becoming available to play on November 12, 2007. The game has received almost universal praise, winning multiple awards at gaming websites, and has been complimented on its storyline, visual elements, realism, and quality of its multiplayer.

Call of Duty: World at War is a first-person shooter video game developed by Treyarch and published by Activision for Microsoft Windows, Nintendo DS, PlayStation 2, PlayStation 3, Wii, and Xbox 360. It is the fifth installment in the Call of Duty series excluding expansion packs. The game's setting returns to World War II, after the previous title Modern Warfare's modern settings. It focuses on the Pacific Theater and Eastern Front of World War II in the Microsoft Windows, PS3, Wii and Xbox 360 version. The title, game details and estimated release date were announced on June 23, 2008 and the game was released worldwide between November 11, 2008 and November 14, 2008. A Windows Mobile version was also made available by Glu Mobile and different storyline versions for the PS2 and Nintendo DS were made, but remain in the World War II setting. The game uses an enhanced version of the Modern Warfare's game engine with increased development in audio effects.

Halo: Combat Evolved is a first-person shooter (FPS) video game developed by Bungie Studios. The first game of the Halo series, it was released on November 15, 2001 as a launch title for the Xbox gaming system, and is considered the platform's "killer application." With more than five million copies sold worldwide as of November 9, 2005,[7] Microsoft released versions of the game for Microsoft Windows (developed by Gearbox Software) and Mac OS X in 2003, and the surrounding storyline was adapted and elaborated into a series of novels.

Halo 2 is a science fiction first-person shooter video game developed by Bungie Studios. Released for the Xbox game console on November 9, 2004, the game is the sequel to Halo: Combat Evolved. After its initial release, Halo 2 was the most popular video game on Xbox Live, holding that rank until the release of Gears of War for the Xbox 360 nearly two years later. By June 20, 2006, more than 500 million games of Halo 2 had been played and more than 710 million hours have been spent playing it on Xbox Live; by May 9, 2007, this number had risen to more than five million unique players on Xbox Live. As of May 9, 2006, Halo 2 is the best-selling first-generation Xbox game with 8 million copies sold worldwide. As of September 25, 2007, Halo 2 is the fifth best-selling video game in the United States with 6.3 million copies sold in the US alone. The game features a new game engine, as well as using the Havok physics engine; added weapons and vehicles; new multi-player maps; and a continuation of the storyline from Halo: Combat Evolved. In the game, humans, who have developed faster-than-light travel and colonized hundreds of worlds, have been engaged in a war against a collective of genocidal alien races, the Covenant. The player assumes the roles of Master Chief and the Arbiter, and fights enemies on foot or with a collection of alien and human vehicles. Critical reception of the game was generally positive, with most publications lauding the strong multiplayer component; at the same time, the campaign was the focus of criticism for its cliffhanger ending.

Halo 3 is a first-person shooter video game developed by Bungie Studios exclusively for the Xbox 360. The game is the third title in the Halo series and concludes the story arc that began in Halo: Combat Evolved and continued in Halo 2. The game was released on September 25, 2007 in Australia, Brazil, India, New Zealand, North America, and Singapore; September 26, 2007 in Europe; and September 27, 2007 in Japan. On the day before its official release, 4.2 million units of Halo 3 were in retail outlets. Halo 3 holds the record for the highest grossing opening day in entertainment history, bringing in US$170 million in its first 24 hours, going on to gross US$300 million in its first week. More than one million people played Halo 3 on Xbox Live in the first twenty hours. As of January 3, 2008, Halo 3 has sold 8.1 million copies, and was the best-selling video game of 2007 in the U.S. Halo 3's story centers on the interstellar war between 26th century humanity, led by the United Nations Space Command, and a collection of alien races known as the Covenant. The player assumes the role of the Master Chief, a cybernetically enhanced supersoldier, as he wages war in defense of humanity, assisted by human Marines as well as allied alien Elites led by the Arbiter. The game features vehicles, weapons, and gameplay not present in previous titles of the series, as well as the addition of saved gameplay films, the Forge map editor (which allows the player to perform modifications to levels), and file sharing. Overall, the game was well-received by critics, with the Forge and multiplayer offerings singled out as strong features; on Game Rankings, Halo 3 ranks as the sixth highest rated Xbox 360 game to date.

Combat Arms is a free First-Person Shooter made by Nexon Corp. It is entirely a multiplayer game with no single-player mode (although the Korean Version has a scenario/co-op mode), and currently contains 5 game modes: Elimination (Team Deathmatch), One Man Army (Deathmatch), Capture The Flag, Search & Destroy, and Spy Hunt. Players who start a game are able to choose the map as well as in-game settings, including game mode and the types of weapons allowed. The game master changes to the next player in line automatically if the original master leaves. This is possible because games are hosted on Nexon servers, not by the master player. Players can attain moderator status by paying ingame-cash for an "Elite Moderator" position, which allows them to kick out players.
http://www.combatarms.nexon.net

Counter-Strike: Source (abbreviated CS:S) is a first-person shooter computer game developed by the Valve Corporation. It is a complete remake of Counter-Strike using the Source engine. As in the original, Counter-Strike: Source pits a team of counter-terrorists against a team of terrorists in a series of rounds. Each round is won either by completing a mission (such as detonating a bomb or rescuing hostages) or by eliminating all members of the opposing team.