First off, there download link for Ultizurk at the RPG page says "Click here to download Need for Speed", and the indicated file size is also wrong.
In fact, the game in question is actually called The Great Ultizurkian Underland v5.5. Here's an original, supposedly unmodified distribution (the ZIP file on the site has 10 extra files with the dates from 2010, supposedly saved games):
http://cd.textfiles.com/gpack2/GUZUV55/GUZUV55.ZIP
Another shareware game in the series is Ultizurk III: The Guildmaster's Quest, which you can get here (v1.1.):
http://cd.textfiles.com/gigagames3/DOS/RPG/ULTIZR3.ZIP
This fan website (Wayback Machine copy) lists other games in the series, but I'm not sure if those are shareware (Ultizurk II supposedly isn't, but I don't know if the same applies to the first game).