Corruption 8, first try. Team was... cleric, bard, druid, into bloodmage, then fallen... i.e. all healer, all the time, or at least as close as I could get to it. First act, well. First act almost killed me. Beat it with three morale left.
Second act? Second act I just flat flawlessed. Flawlessed the whole act, straight.
... third was a bit more mixed, usually losing one guy per fight with some flat losses along the way (bloody conduits), but ultimately. Ultimately, I won the run, with a mono healer spec'd party.
It probably shouldn't have worked, and the cleric coming in as MVP dps in the final boss fight was a little silly (its passive, plus symbiote+mana regen items and one that gives major blessings on active use resulting in like 200+ attack with capped out speed
and mana reduction by the end of the fight), but... it did. It did work, ha.
e: Legend Creatures tells me I can brag about beating the game now :V
Beat difficulty level five after four or five tries. There's definitely a noticeable jump in difficulty with level 5, heh.