Effectively creepy but in the end you just want to talk about how little sense it makes

Rating: 7/10 (24 September 2019)

Us creates a great atmosphere of creepiness and some memorable moments. It is well acted and exciting. It also has so many utterly nonsensical aspects to story, plotting, and world building, that everyone who writes a user review marks it as spoilered so they can list the ones that bug them the most. As someone elsewhere noted, Jordan Peele, who wrote the virtually perfect Get Out, was so focused on creating an allegory about class privilege that he couldn't bother to create a story that made even a tiny bit of sense.
I still enjoyed this movie, but I'd rather talk about some of the things it got wrong that I haven't seen mentioned elsewhere:
**** SPOILERS BELOW ****
First off, t makes no sense at all that, as it appears in the movie, the underground folk kill everyone in the world except this one family. It's not unusual for a horror film to have a final survivor, smarter or luckier than the rest, out of, say, 8 people. But seriously, EVERYONE IN THE WORLD?
And apparently this one family lives because they have the only doppelgangers who aren't ruthlessly efficient. Why this cat-and-mouse game while with that white family it's over in 30 seconds?
Even little things are done with an almost purposeful obliviousness to common sense, as when the mom is unable to drag the light wooden coffee table she's handcuffed to even one inch.
Then there's the big twist (the mom is from the underground!) that makes no sense for an almost infinite number of reasons (you'll find many enumerations on this site). Again, one reason that I haven't seen mentioned is if the mom is from the underground, and, as is shown elsewhere, the underground people are stronger and faster, then why couldn't she easily vanquish her doppelganger? It's really as though the whole movie was filmed without the twist being intended, and then it was thrown in at the last minute. However, I don't think that's the case, because it's kind of an obvious twist. I think Peele just didn't care that it was BS.