I love how this "little details" thread has turned more into "miscellaneous tips and tricks". As well as gotten so cumbersomely huge that people are probably going to start repeating "details" soon without even realizing it.
Well I made an attempt at recreating my own winning character, but got tired in the attempt. I was having some trouble finding decent legwear, and a glowey mace was tough too...
Aww. My metal-man challenges are gone. I only remember Ironman. I'll rephrase:
You cannot visit any level twice, save only UT2, and then only if you went to UT4 first. Once you go to UT3 you cannot return to UT2. Once you have Elpuri's head you're allowed (of course) to return back up the GC.