SUDS (Single User Dungeon System) is developed by Andy Elliot, whose pages at www.btinternet.com/~sudslore are the primary information source. Good news! originally shareware, it is since October 2001 freely available without charge.
SUDS runs only under Windows (95, 98, ME, NT). Unlike most of the authoring systems featured here, it is not based on the traditional model of compiled source and interpreted binary files. Instead, as with ADRIFT, a game exists only as a single binary file which is created by the Constructor (a series of specialised editors) and read by the Player. Both components use a Windows-style graphical interface, and are largely mouse-driven.
Quoting from the FAQ for the rec.arts.int-fiction newsgroup:
If you want a Windows-only program with a good IDE and dialog-box-based programming instead of text-based programming, and you do not mind that SUDS players converse with your game by a simple point and click interface, then SUDS is probably the system for you: it shows every sign of being written with care for that purpose. The main disadvantages in comparison to more traditional systems are that it is a Windows-only program and doesn't have a parser-based user interface like most IF.
Read the complete SUDS entry at www.plover.net/~textfire/raiffaq/FAQ.htm#:SUDS or the entire FAQ at www.plover.net/~textfire/raiffaq/.
The SUDS version of "Cloak of Darkness" was written by Roger Firth (email@example.com).