I agree about the frogs in the mines. I tried hitting them with Cripple (the one effect not immune to) and nothing happens because their armour is too high. Oh, and extra lives does naff all as there are too many
I like the Protector TD games (they're not RPGs though). Only problem I get with this one is that the "hire two necromancers then win map" criteria for the "Life, Death and Honor" badge doesn't seem to work