I think they needed a more coherent "story" for it. The first greenhouse isn't a bad start, and I liked the bit with the pond, but there were too many stretches where nothing happens; the plants themselves are, well, just plants; and the finish was weak (yet another building filled with strobe lights). I was glad to see the "Lady of the Gardens" character in there, but they needed to do more with her. Perhaps they should change it up next year to a possessed garden that's trying to claim your soul (that way, they could still keep the zombie groundskeepers and give the Lady more to do).