It's an Inform game which is the same format Infocom uses if it ends in .z5 or .z8 or maybe .z3. If it ends in just .Z, that is, the Z is uppercase, it's compressed with the old Unix compress. Gunzip will handle it just like a regular .gz file. Don't use ftp.gmd.de. It's no longer being maintained. ftp.ifarchive.org is the new IF home, but it is painfully slow. I suggest ftp.plover.net as a good mirror with plenty of bandwidth. It runs on a Linux server, too.
