Fatal Labyrinth/Secrets

Fist fighting
Discard your current weapon and you can fight enemies with your bare hands. This has no real purpose, but it works well against enemies that can devour your gear.

99 AC
Every time you equip a bow your AC drops by 1. While this might seem like a bad thing, there's actually a trick to it: once you have two bows, repeatedly alternate between them. Once your AC drops to 0 equip one again and it will roll over to 99. This will make you incredibly powerful.

Blessed Weapons
If you have a scroll of Weapon Strengthen, use it on a cursed weapon (Blood Sword, Golden Axe, Skull Lance) to remove the curse. Its strength value will be listed as 1 but it is actually very powerful and can easily defeat most enemies in a few hits.