I wanted to see if the game was beatable with tier-3 equipment. The rule is simple: never equip any item whose description includes "tier-4" or "tier-5".
It turns out it's possible! I played with a gladiator, and the "swarm intelligence" challenge.
My weapon was a sword +1 (best tier-3 weapon that I could find), upgraded to +6 and augmented with a kinetic enchantment.
The armor was a chain mail +2 (again, best I could find), upgraded to +13 and with an anti-magic glyph.
I was lucky to find a good selection of rings. The RoF +3 was a gift from the imp in level 17 or 18, so I only had it for the final floors. The RoE was found at +0. The RoW helped in the first half of the game, and the RoM provided lots of bonus damage to my low-tier equipment.
I was also lucky to get a WoC +3 from the wizard. The WoF is always useful to slow down opponents.
The entire run was done without any help from artifacts. The ToF is the only artifact I found in the entire dungeon, and that was in level 19. Since I had stashed four or five Scrolls of Magic Mapping, I never used the Talisman.
In the end, it wasn't too difficult. What I missed most was the feeling of power from one-shotting mobs with a well-upgraded tier-5 weapon while feeling invulnerable with a plate armor.
I'm going to try a Tier-2 run next (with a similar rule), maybe without challenges. I haven't decided what class to use. Has anyone tried it before?
I think I'll try a Monk next.
She gets benefits for using under-tiered armor and weapons, and the free heal you can do with her is always nice