Oh it's absolutely brutal! Haha! But it's such an addictive little game and so easy to fire up a new sanctum (I enjoy doing that in itself and trying different strengths for different rooms)
I'd say the armoury too, like sending the guardian out to do his duty!! .. But I also enjoy getting the Palisades up and running early, before I then take damage and lose 1 ballista after the next (through crossing them out as damage)
I've not tried your expansion yet with the guard dog/statue thing!! .. Think I'd get too attached to the pup! Lol!