i found my self disappointing with this game since i waited 5 years for it for a 1 day long campaign (in legendary)and a incomplete multiplayer not to talk about all the glitches anyway here are the facts
halo ce: The first game of the Halo franchise, it was released on November 15, 2001 as a launch title for the Xbox gaming system,[1] and is considered the platform’s “killer app”.[7] With more than five million copies sold worldwide as of November 9, 2005
halo 2: On release, Halo 2 was the most popular video game on Xbox Live,[5] holding that rank until the release of Gears of War for the Xbox 360 nearly two years later.[6][7] 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;[8] by May 9, 2007, this number had risen to more than five million unique players.[9] Halo 2 is the best-selling first-generation Xbox game[10] with at least 6.3 million copies sold in the United States alone
halo 3: On the day before its official release, 4.2 million units of Halo 3 were in retail outlets.[2] Halo 3 grossed US$300 million in its first week.[3] More than one million people played Halo 3 on Xbox Live in the first twenty hours.[4] To date, Halo 3 has sold in excess of 11.5 million copies, making it the fifth best selling Xbox 360 game of all time, the best selling game in the Halo franchise, the best selling Xbox 360 exclusive title and the best selling first person shooter on the console
halo 3 odst: Upon release, ODST became the top-selling Xbox 360 game worldwide. The title received generally positive reviews from critics, who praised the atmosphere, music, and story approach. Reviewers were divided on whether the relatively short campaign and included extras were enough to justify the game’s US$60 price tag. The game was the top-selling title in the United States in September 2009, and sold more than 3 million copies worldwide. Softpedia, Time and Wired were among publications that declared the game one of the year’s best.
halo reach: Halo: Reach grossed US$200 million on its launch day, setting a new record for the franchise. The game sold well in most territories, moving more than three million units its first month in North America. Critical reception was positive; reviewers from publications such as IGN, GamePro, and Official Xbox Magazine called it the best Halo title yet.
halo 4 actual players:333,073 i have found no more data about halo 4 but its not the best halo so far i will put more information when i found it.