Adventure II
An early (British) expanded version of the mainframe adventure game

(aka Advent440)

Jack Pike, writing in to the May 1979 issue of Practical Computing, discussed his efforts of porting the mainframe Adventure from non-standard Digital Fortran to standard Fortran; creating a new version of Adventure... //

The source code for the game was recovered by adventure historian Mike Arnautov, who has his own website about that particular version of the game (as well the history of the mainframe program and its many other ports). https://www.mipmip.org/adv440/index.html. //

There are several articles online about Adventure II. I would recommend reading Jason Dyer's exploration of the game, written as part of his All the Adventures series.
https://bluerenga.blog/tag/adventure440/?order=ASC