Based on the code of Fangorn's CliFrotz 1.6, CellarDoor maintains support for Z-Machine story files, while adding support for Glulx stories, as well as Z-Machine and Glulx stories wrapped in the Blorb file format (.zblorb and .gblorb files).

CliFrotz was based on the Frotz v2.43 interpreter. Frotz is an Interactive Fiction interpreter that plays Z-Machine (Infocom, Inform, Z-Code) games such as Zork and Hitchhiker's Guide to the Galaxy. CliFrotz supported V1-V8 games and V6 MG1 graphics.

CellarDoor adds Glulx support via the Git interpreter (1.2) and uses a (rather) modified version of the CheapGlk library (0.9.0).

It supports JPEG and PNG graphics, if they are found in Blorb files. It requires a hi-res screen, OS4 or later, an expansion card and the large dynamic memory area available from OS4 onwards. If your handheld does not meet these requirements, you may want to try Frobnitz, PilotFrotz or Kronos.

Update Description:

• Added default color to the Preferences. Note that choosing custom colors might cause problems with games where some, but not all, colors are specified.
• Adding color required that we change the screen-compression scheme used for
• Autosave. Now using SysZLib for Autosave/load, included in the installer.
• Increased word/verb list size to 20, and grew the forms to match. 20 feels like a good, final, never going to change again kind of number to me.
• Numerous fixes to the drawing engine, eliminating some unnecessary refresh overhead and getting some UI elements to clean up better after themselves
• Added 3 pixels to screen height and adjusted bottom bar color.
• Fixed crasher in 'Delete' in the Save Game form.
• Glulx: Now has 32 visible windows permitted (64 total). Fixes Jon Ingold's Dead Cities, and probably some other games I haven't tried.
• Glulx: glk_window_erase_rect() and glk_window_fill_rect() were using the wrong area of the screen. Fixed.
• Glulx: Improved sizing of graphic windows upon Autoload.
• Glulx: Random seeding now works properly.
• Glulx: Fix for broken Autoload of complex window setups in Glulx games (CoS, for instance).
• Glulx: Fixed mouse event bug, whereby only the first mouse event was captured under some circumstances, while all others were ignored.
• Glulx: Improved Autoload's handling of style hints.
• Fixed completely broken mouse events (broken in 1.0.2).
• Autoload failure is now more graceful.
• Word/Verb-popup no longer strips apostrophes.
• Rewrite of word/verb list code; somewhat more efficient now, doesn't require constant database access.
• Lots of drawing and performance fixes in the Notes window. No longer feels like an afterthought.
• Added standard Edit menus to Words, Verbs and Notes. Using the Command Toolbar has never been so satifying.
• Renamed the ambiguous "Free Heap RAM" to "Check Heap RAM", which now reports in KB, rather than in bytes.
• Numerous minor fixes to Autosave/load. 'down' can now be used to get out of MORE. 'down', if there is no 'next command' in the history, erases the current line.
• Cosmetic changes (border around the more button and new button graphics, cursor color, etc.).