Page "Id Software" Paragraph 33

During its early days, Id Software produced much more varied games ; these include the early 3D first person shooter experiments that led to Wolfenstein 3D and Doom — Hovertank 3D and Catacomb 3D.

There was also the Rescue Rover series, which had two games — Rescue Rover and Rescue Rover 2.

Also there was John Romero's Dangerous Dave series, which included such notables as the tech demo ( In Copyright Infringement ) which led to the Commander Keen engine, and the decently popular Dangerous Dave in the Haunted Mansion.

In the Haunted Mansion was powered by the same engine as the earlier Id Software game Shadow Knights, which was one of the several games written by Id Software to fulfill their contractual obligation to produce games for Softdisk, where the Id Software founders formerly were employed.

Id Software has also overseen several games using its technology that were not made in one of their IPs such as Shadowcaster, ( early-Id Tech 1 ), Heretic, Hexen ( Id Tech 1 ), Hexen II ( Quake engine ), and Orcs and Elves ( Doom RPG engine ).