Thinking about it more, I'm not even sure which mystery we're supposed to be focussed on, or is meant to be left unresolved.

Is it - who created the faery circle, and why?

Is it - where did The Doctor go, and will he reappear?

Is it - what is the woman saying to everyone to make them act that way?

Is it - how does the timey-wimey resolution work?

I don't mind being temporarily confused, if I get a moment of clarity eventually. I don't mind one or two ineffable mysteries implying a greater universe that we may never fully understand.

But this one had too much of nothing making any sense at all, and then she woke up and it had all been a dream!

(Space Babies was definitely the good kind of silly though, and I thought The Devil's Chord had a good balance of tense and scary with the silly all bound up together in Maestro. Boom also fun, if a little on the nose at times - I do prefer it a bit more when The Doctor leads other people into figuring out the answers for themselves, rather than just beating them over the head with the exposition stick - and interesting themes reminiscent of the 12th Doctor episode Oxygen.)