So I just played through the campaign, and on the final level, "United Kingdom", there is either a set of very strange features, or bugs.
Creatures can hardly attack. Wizards cannot cast spells, despite them being in their skill set. Even during possession, nothing is shot. Melee creatures' attacks are near useless as well, as they don't hit anything. I tunnelled into a new area and was attacked by several Heroes, and out-numbered them heavily, but the battle took extremely long as 99% of their hits were not landing, on either side. I had to speed up the game to get past it.
Unfortunately this also means I can't progress because setting my creatures on enemy doors is also fruitless. I don't think a single hit is landing.
After a while my Hatcheries stopped spawning Chickens too, so my creatures are starving and angry. The only apparent option is Armageddon, but there's an enemy keeper and a ridiculous number of hero units around the map, far too many to take on in one go.
I'm finding to hard to tell what's intentional and what isn't. I can only cast lightning around the dungeon heart but not in outer areas, even on my own claimed land. I can't create more than 12 imps either.
Can anyone shed some light on what's happening here?
Edit: Another peculiarity was that every few seconds the red text "Frame Rate 0" would pop on screen but disappear within a fraction of a second.