I once had a warroir with brimstone armor and an elastic sword. I stood in a room full of burning traps and used a scroll of rage. When the monsters came running I just kept snapping them onto the traps. Quite amusing too.
I also get a good laugh when the leaping demons jump into pits, killing themselves. Or, Ratmogrifying an Evil Eye as it hovers over a pit. Did you know that rats can't fly?
Another method I like to use is throwing a Stone of Aggression at the King after he has summond his minion's and just let them attack him.
An upgraded wand of lightning is another effective tactic.
That is what I love about these games, figuring out HOW to beat it. It isn't just about hack-n-slash.