Unity Underground

Produced by: Kweepa (development since taken over by Massimo)
Website: Unity Underground @ itch.io
Source Code: OpenUnderground @ GitHub

Unity Underground is a complete engine recreation of Ultima Underworld, built by Kweepa in the Unity game engine. Kweepa started work on the project in 2015, building on research that earlier Underworld hackers had shared. The project replaces the original’s sprites with new 3D models and adds new sounds: all enemies are fully modelled and animated, as are all inventory and environment objects, and it adds unique audio and particle effects. It still needs the original game data to run. On launch, the player can point it at the GOG installation folder for Ultima Underworld, or have it search for the files.

The game supports an Xbox-style controller and, since a June 2026 update, mouse and keyboard. Later updates added a texture override folder, so that players can replace the game’s wall, floor and door textures with their own PNG or JPG files. In August 2026, Kweepa released the source code on GitHub. Some licensed asset store assets had to be removed first, so the open source version doesn’t look or sound exactly like the release build available on itch.io.

In September 2026, development was handed over to Massimo (“unbroken75“), who aims to make the recreation more faithful to the original game while adding modern features for new players. His first release reworked the combat and magic mechanics, added quicksaves and autosaves, made the Search and Traps skills relevant again, and fixed a long list of bugs.