A mod of Zork I Solid-Gold.
What is this Repository?
Zork I with all puzzles changed (to make the game interesting to those who have already played it), and to add a companion NPC (Dr Grue). The idea is that Dr Grue lands on this planet with his assistant, and we slowly discover that it's a "game planet". Dr Grue gives out hints where necessary. Towards the end game, things start to go awry.