Huh. Well, that wasn't quite what I expected (which may or may not be for the better). I clearly set myself with the expectation of a folk horror story, and while that was partially true, it instead was more of an alternate future history of Ruby and how she saved the world from a political monster, but then turned itself into a paradox. Obviously Davies played on my expectations with the evening scene in the pub with Siân Phillips (!) and company playing a gag on poor Ruby's fears and worries about a broken fairy circle, so well played there.
But in the end, I'm not quite sure what the point was. As I read back at what everyone else said, I see I'm not the only person who felt like there was something missing, something deliberately left out to be explained later, and I agree that ultimately hurt the episode. I'm all for lampshading expectations (even if when it's against a story style that I wanted to watch) but there still needs to be standalone plot reasoning.
I agree with jaime that "73 Yards" doesn't have the emotional impact of similar stories like "Turn Left" and "The Girl Who Waited" because, like Mr Awe noted, it asked too many questions without providing any satisfying answers. I think that's all a shame since I think there was something wonderfully sinister in the potential of this story that wasn't successfully pulled off as a result.
I do hope that when do get the full story, "73 Yards" will stand stronger but I just wish it didn't need that extra explanation in order to work.