Thank you very much for the tip, although that is basically what we're doing already (I even tried other variants this morning) for this and other dungeons. Flashing the whole grid as dirty doesn't slow the game much (I never noticed anything). However, for some reason, this is the only place where we still have this kind of bugs... Looks as if the RemoveWallEvent wasn't properly setting the dirty flags around the wall before reapplying the tileset.
Anyway, I'll keep digging to see if I find another way to fix it.
@shade_of_ox
Seeing you tearing through the EE that quickly is almost frightening. I certainly don't have your or The Avatar's skill level, and I sometimes wondered if his designs weren't too hard, but you are brilliantly demonstrating that he set the difficulty right on the spot.
I hope you'll try the Curious or VT version of those dungeons next, so that we can hopefully see you suffer a little

A few comments about your earlier comments:
As The Avatar pointed out, you missed the most defining feature of Fido: +1 base damage per level (although right now this feature is very much broken)
On top of that, Fido and The One Horn have the common advantage of keeping giving you their boost on prestige levels.
It make the horn better than Dragon Scale in long runs like VGT, or for screwing parties.
About the Shadow Heart, I'm quite surprised that the first build that comes to your mind are regen fighters rather than Spellcasters.
Also, Abtitheist Collar won't protect you from JJ. His not punishing you in the regular sense. He's just being himself.