Got this along with Victory Sword (for defeating 100,000 enemies in one run as Queen Sigma) as my very last few achievements to complete this game.
Took many attempts with different characters before finally being able to just survive long enough in this zone. Not only do enemies get even tougher and more numerous with time, but you won't find any pickups from destroying torches other than coin.
My advice is to try and save this (along with Victory Sword) till the very end, playing as Queen Sigma. As you level up, be sure to get weapons and abilities that work well together. including evolving your weapons. By the time all my weapons and abilities were evolved and fully ranked, I didn't even need to move to stay alive.
P.S. Turning on 'Limitless Mode' will not keep you from getting this achievement!