Minima
Minima is a game built using a custom engine for PICO-8, featuring gameplay and graphics similar to the Commodore 8-bit releases of Ultima II, Ultima III, and Ultima IV, but with an overall length more similar to Ultima I. Its plot is unrelated to the Ultima games. The protagonist starts unarmed in the land of Miskatonia not too far from the Town of Saugus. Unfortunately an evil being known as the Faxon has been sending legions of orcs, undead, and sorcerers out to make life difficult for the good folks of Miskatonia. It's up to the protagonist to explore the land, talk with the people, figure a few things out, and get strong enough to defeat the Faxon.
The game can be played on MS-Windows, Mac, Linux, PocketCHIP, Raspberry Pi, and online on many platforms.
The manual for the game can be downloaded as either a PDF or an ePub.
At least one other Ultima-influenced game, Anteform, has been written using the Minima Engine.