PlatinumGames was formed when Seeds Inc., a company created by former members of Clover Studio including Atsushi Inaba, Hideki Kamiya and Shinji Mikami, merged with ODD Corporation. PlatinumGames' first five titles were published by Sega.
In the second half of 2010, Shinji Mikami and a number of other employees left the company to form Tango Gameworks.
In early 2008, PlatinumGames announced a four-game deal with Sega. The first of the games to be released was MadWorld for the Wii, an extremely violent 3D beat 'em up with humor elements. The second was Bayonetta for the Xbox 360 and PlayStation 3, marking Hideki Kamiya's return to the 3D action genre. The third game, Infinite Space, was a Nintendo DS JRPG developed in collaboration with developer Nude Maker. The fourth game was Vanquish for Xbox 360 and PlayStation 3, a science fiction third-person shooter directed by Shinji Mikami.
In January 2011 PlatinumGames announced their fifth game, Anarchy Reigns (Max Anarchy in Japan), a multiplayer beat 'em up which was released for Xbox 360 and PlayStation 3 in January 2013. Like previous PlatinumGames titles, Anarchy Reigns was published by Sega.
At the 2011 Spike Video Game Awards it was announced that PlatinumGames would be collaborating with Kojima Productions on Metal Gear Rising: Revengeance, a third person action game starring Raiden. Platinum Games handled the gameplay side of development with Kojima Productions taking care of the story and cinematics side and Konami publishing (their first game to be published by a company other than Sega). Metal Gear Rising: Revengeance was released on February 19th, 2013.
Platinum is also working on Bayonetta 2, a Wii U exclusive. It is set to be released in 2013.
PlatinumGames has a video podcast that goes behind-the-scenes of current games they're developing. Hosted by JP Kellams, the show has interviews with various employees working on their titles. It is available via iTunes or RSS feed.