My first try at a perma run ended in the swamp, Not to mobs per se, but to poison. So I feel your pain.

Fight was over, all the attackers were defeated and all I could do was watch as my remaining health ticked down in a green mist (yeah, no potions as I figured I really didn't need them...yet)

But these 'rogue-like' runs just make you want to jump back in, start anew and not make the same mistakes you jut did.

Have not tried a no bosses run yet. Need to perfect my 'Troll' mining skills first I think.