Crowther & Woods' Colossal Cave (aka "Adventure"), converted to Megamax C by Marvin W. Rasmussen. (Source is not included in this archive, but there is a pointer to the source.)
Operation Blue Sunrise, by Creative Insanity. Atari ST emulator disk image.
The Crimson Crown (Transylvania II), by Antonio Antiochia. Originally released commercially by Penguin (later known as Polarware). The current copyright holder, Mark Pelczarski, has permitted free distribution.
Atari version of Dungeon, the game that evolved into Zork. Source included.
Mindfighter from Delta 4, now free according to their web site.
Beyond the Tesseract version 2.0p for the Atari ST, by David Lo. (Source code is in games/source/tess.tar.gz)
Titan Find from Delta 4, now free according to their web site.
Unnkulia One-Half: The Salesman Triumphant, AND Unnkulia Zero: The Search for Amanda (playable demo). Both are version 1.0, by D. A. Leary.
Unnkulian Underworld: The Unknown Unventure version 3.0 by D. A. Leary.
Unnkulian Unventure II: The Secret of Acme version 3.0 by David M. Baggett.