Cloak of Darkness is a short text adventure game created by Roger Firth, meant as a benchmark for comparing between interactive fiction engines. For this reason, many different ports exist for different engines and platforms. The goal of this game is to find a message inside an opera house. The game begins with our protagonist wearing the titular Cloak (no, not me 😛).
This run was made with a port by Richard Bos for the ZX Spectrum written in The Quill, a text adventure engine that was very popular in the ZX's lifetime. The port also uses The Illustrator, an add-on that supports graphics. The game's five ports were released as freeware. For more info, I uploaded the game's manual on my Neocities.