 It was released for mobile phone on May 1, 2006 before being ported to the Nintendo DS on November 15, 2007.The game is based on "Doom RPG"s engine and is id's first original intellectual property since "Quake".The later DS port of the game included graphical enhancements, such as 3D environments and camera cutscenes, along with improved character sprites, two new levels and the use of the touchscreen feature.