Cloak of Darkness by The Pixie

The Cloak of Darkness is a specification for an adventure game that has been created in numerous systems, with the purpose of giving prospective authors some idea of what is involved in each system. You can learn how it was created here:
http://docs.textadventures.co.uk/quest/cloak_of_darkness.html

From the specification here:
http://www.firthworks.com/roger/cloak/