yup...just tried it myself. did poison from weapon smith instead of whetstone, but ya...just give yourself a bit of armor for the initial spikes when you find them, since they proc before candle, and you're basically a shoe in for however far you wanna go...a little too boring tho
Yeah, after getting a few floors into endless mode, I gave up after having to click it multiple thousand times per battle, even with animation speed fully up. The game started lagging from so many things ticking. Wanted to get to the spike-generating enemy just to confirm, but never found them.
So this is pretty great for doing the initial run, but beyond that, it's more of a theoretical victory, knowing the only enemy you can lose to is the unceasing march of time ;P