Released by Infocom in 1987.
Beyond Zork is a technically unique game. It's one of the latter releases from Infocom, and as such, it was a huge game (Version 5 file). I never got it because it required Commodore 128 and I've always been a die-hard C64 user =)
Beyond Zork was also interesting at the time because it used crude graphics (based on graphical characters) to display game map that is updated when the player explores the area. First Infocom game to feature graphics! Also, the game featured redefinable function keys. Also, the game had semi-RPG-style character stats that were displayed on screen. The game even featured mouse support (on platforms where mouse was available) to move on different areas by clicking there.