I must say that I have a TWD Pro and really love it. I have an Ironman too and I really think TWD is a lot tougher than Ironman believe it or not.
But fun fact: Those 2 described wizard modes in the Stern video are not yet implemented in the latest code. Hopefully the video is a good sign that the update with the wizard modes is coming sooner than I thought.
I had collected all the multi-kill weapons and the DMD showed the word HORDE for a moment but gameplay just continued normally. No wizard mode started.