PRETZIL stands for PRETZIL Realizes Emulation of The Z-machine In Lisp, a name chosen to be a deliberate misspelling of a word to make it easy to search for in Google. This was before I discovered that a large number of people don't know how to spell 'pretzel'. Win some, lose some.
Pretzil is, essentially, still a prototype. It runs Z3 files, and has some hooks for other versions of the format, but needs a bit of work before it can support Z4 (AMFV) or Z5/Z8 (most recent games). It does use McCLIM (as if you couldn't guess from the screenshot below). I make no claim that the code is particularly wonderful.
You will need a game data file in order to use this software. These images are fairly easy to find online, but finding the Z3 type that are supported by Pretzil may be trickier (although apparently Zork is fairly easily available).
|pretzil.tgz||Released 2006 February 24th|