Return to Castle Wolfenstein is a first-person shooter video game published by Activision, released on November 20, 2001, for Microsoft Windows and subsequently for PlayStation 2, Xbox, Linux and Macintosh. The game serves as a reboot of the Wolfenstein series. It was developed by Gray Matter Studios and Nerve Software developed its multiplayer mode. id Software, the creators of Wolfenstein 3D, oversaw the development and were credited as executive producers. The multiplayer side eventually became the most popular part of the game, and was influential in the genre. Splash Damage created some of the maps for the Game of the Year edition.A sequel, titled Wolfenstein, was released on August 18, 2009.