Zork I (Microcomputer Version) by Infocom

The Hitchhiker's Guide to the Galaxy, by Steve Meretzky and Douglas Adams (Infocom)

Mainframe Version of Zork (Infocom)

A fast and compact library for writing text adventure games for the Z-machine running on 8-bit computers as well as other platforms.

Planetfall, by Steve Meretzky (Infocom)

Zork I (Microcomputer Version) (Solid-Gold Edition) by Infocom

Zork III (Infocom)

Zork II (Microcomputer Version) (Infocom)

A simple Z-Machine implementation in a single C file. Now with online multiplayer! :)

A Z-machine interpreter for the Commodore 64 and similar computers

Deadline by Marc Blank (Infocom)

Beyond Zork: The Coconut of Quendor by Brian Moriarty (Infocom)

The Restaurant at the End of the Universe (Incomplete, Unreleased) (Infocom)

Bureaucracy, by Infocom

Enchanter (Zork IV) by Marc Blank and Dave Lebling (Infocom)

Trinity by Brian Moriarty (Infocom)

A Mind Forever Voyaging, by Steve Meretzky (Infocom)

Suspended by Mike Berlyn (Infocom)

Infidel by Mike Berlyn (Infocom)

Stationfall, by Steve Meretzky (Infocom)