fuck it, did it with the candle, after botching it vs Hurtily, and no centipede on either envy/charge floor. spent hours autistically trying to get enough damage to do it vs floor 1 Hurtily, but those faggot minions dying @ 4 surgery made it hard to 99x99; I had to spend SO MANY turns passing with the fucking barbs for a pittance of 3x3 every turn to build up their count, and even with a ton of bench passives being stacked, and EGO gifts focused on damage, I'd break 15k, but the highest I got was 15454 and that wasn't enough because there was like, 600 gloom damage. With a crit, it might be possible, or hell, on floor 2, but that singular protection buff might have been the difference between getting it on floor 1.

you don't actually need to burn a whole run when doing the 15k damage achievement, so you can just ++ all the starlight buffs/grab specific gifts, and bail once you hit the 15k to retain it all. i imagine it's the same for the 80 clash achievement, right?