The Bungle Brothers, written for the the BBC Micro and released into the public domain. Ported to the Archimedes in BBC BASIC 5 by J.J.Farmer.
Dragon Adventure, a simple text adventure for players aged 9 and over, by William Stott. (a Z-code version is in games/zcode/dragon.zip, and a Glulx version is in games/glulx/dragon.zip)
Dungeon, the more or less public domain version of the original MIT Zork, version 2.7A, 11-Mar-91, ported to the Archimedes by Julian Arnold. (the original C source code is in games/source/dungn27s.zip)
Frankenstein Adventure. Originally published in the Cload TRS-80 magazine, October 1981 (author unknown), and converted to Inform by William Stott. (a Z-code version is in games/zcode/frankie.zip)
The Great Adventure, by Gordon Pickard
Kryten 98, by Robert Titman. Play as Kryten from Red Dwarf as he tries to find the missing crew.
Prehistoric Time Trip, version 2.00, by David Lodge. A series of three text adventures.
Spheres of Chaos, by Chris Grant (Spark archive) "another simple single-tasking Arc adventure of the old school. As such games go, this is quite good."
The Secret Garden, by The Sleeping Sphinx
World version 1.07 by J. Doug McDonald, ported to the Archimedes and enhanced by Julian Arnold (a DOS version is in games/pc/world107.zip; an Amiga version is in games/amiga/World_1.07.lha; a Macintosh version is in games/mac/World107.sit; source code of the DOS/Unix version is in games/source/worldsrc.zip)