Ultima Underworld II: Labyrinth of Worlds is a 1993 first-person role-playing video game developed by Looking Glass Technologies and published by Origin Systems. As the sequel to Ultima Underworld: The Stygian Abyss, the game is set in the Ultima fantasy universe. Players assume the role of the Avatar—the protagonist of the Ultima series—and adventure through multiple dimensions while seeking to prevent the evil Guardian from achieving world domination. Progression is largely nonlinear and the game allows for emergent gameplay.
Ultima Underworld II began production in April 1992, shortly after the completion of Ultima Underworld; and it was developed in nine months. The team sought to improve upon the foundation laid by the game's predecessor, particularly by increasing the size and interactivity of the game world. The team reused and improved the first game's engine. Development was impeded by insufficient staffing and extensive playtesting, and the rapid production cycle led to burnout on the team.
Most critics gave Ultima Underworld II positive reviews and lauded its graphics, design and nonlinearity. Complaints focused on its high system requirements and unrefined pacing. It has been placed on numerous hall of fame lists since its release. In reaction to the game's difficult development, Looking Glass altered its design approach: they streamlined ideas from the Ultima Underworld series to create System Shock. The team pitched a sequel to Ultima Underworld II multiple times, but Origin Systems rejected the idea. Arkane Studios' Arx Fatalis (2002) is a spiritual successor to the franchise originally pitched as a sequel. OtherSide Entertainment's upcoming Underworld Ascendant will be the first officially licensed entry in the series in over 23 years.